Do you have a contract with them that outlines your responsibilities and, subsequently, your limitations?

Unfortunately Its a v basic contract and only states that we are responsible for managing the website, updating & adding content, keeping website secure, backups and SEO.
it doesn't explicitly say we are not responsible for emails.. although maybe that can be implied as we have never had access to the email accounts/server?

thanks

It turns out they had a virus on one of their PC's and then found themselves on a email blacklist - which was preventing delivery of emails. (form sends from a domain address to a domain address)

I would ask them to explain the part of your agreement that makes you liable for their careless habits. Device security is far out of your purview to monitor.

it doesn't explicitly say we are not responsible for emails.

But it sounds like it also doesn't explicitly say you ARE responsible for them receiving their e-mails.

IANAL (and certainly not one in the UK), but absence of stated responsibility for a service in a contract pretty much means no responsibility for that service. That's what contracts are for- specifying what IS whose responsibility.

my hosting supplier ... have provided me with some email sending logs

That, to me, sounds like the extend of your responsibility.

They have an IT department and it didn't discover the virus on their own machine! Oh dear.
For at least two months they didn't ask why no e-mails? Oh dear.

Imagine, the office coffee machine runs out of coffee and for two months, nobody says anything. Who do you blame? The company who made the machine?
Sounds like your contact is looking for someone to blame, and you are the one they've picked on. That's very unfortunate.

Stay calm, stay professional, don't rise to any threats, don't waste your time tying to prove who's fault it is, simply provide all the support to show you did everything within your remit.

Chase for the payment in the normal routine.

If it escalates you may need to consult a lawyer.

thanks all for your responses.

Have responded to their (vicious) email with a calm fact based response.
Tried to follow up with a phone call - but the MD won't take my calls, so have emailed asking him to call me when he has time.
Let's see what happens...

I suspect that the other company is doing damage control as well, and has probably convinced the client that you are the problem ... not their handling of the email processing. Expect more truculence in the future, sad to say.

For at least two months they didn't ask why no e-mails? Oh dear.

I'm with Engine here, they didn't notice, now it's your fault.

I would add...
Whoever approved any mission critical operations that rely on email delivery, should be fired.
And by approve, it is the client's fault, they approve (you do work, give advice, devise and implement tactics and strategies, but the client ALWAYS decides what is acceptable regarding outcomes and deliverables).
Whether they asked you (or they asked anyone) to setup email deliverables, or they told you to do so, or you decided it on your own, by accepting it as it was, they decided email deliverability would never be an issue for them.
And that decision, was ill-founded then.

In any fast moving online enterprise, if there's never a mistake made, you and the client are going to lose, cuz you're moving too slow.
When #*$!ake happens, that's when you judge your partners... you don't seek to blame, you commit to fixing it, learning from it, then moving on to the next issue.
If they prefer the blame game, over mutual progress, ditch them.

Sever relations if necessary but if there is real money involved that can make or break do your level best to accommodate, explain, show/display, suggest resolutions, develop new strategies, solve the issue. Avoid lawyers resulting from a pi$$ing match if at all possible because NO ONE benefits from that!

As long as you have a paper contract with "four corners" you can act from a specified ground.

NOT LEGAL ADVICE (we can't give it). If you need an attorney, find one of your own choice.

.

Sounds like the MD of the firm are trying to protect himself from the no emails debacle, I wonder why ?

My apologies I forgot to update this thread - so for the sake of completeness - here is the conclusion.

I managed to finally speak to the MD of the firm who told me that he didn't know what was going on but he's had 4 different versions of events from every interested party.
I calmly and factually gave him reasons why it wasn't our fault, and how he could prevent this in the future. He then explained that the company was struggling and the lost emails could have made a big difference to the bottom line.
He thanked me for my call - and said he absolutely wanted to continue working with us.

3 days later I get a Google Webmaster tools verification request in my inbox for their domain. So I go to their website to check for any issues and I am greeted with a brand new website (looks like it was built by themselves in Wix). They have ditched us - analytics not working (they are using a new account - which seems crazy as they had 10 years of data in the existing one), webmaster tools access gone and as they have moved the name servers I can't even access the old site.

I was really shocked .. but more disappointed - so I emailed again, enclosing a copy of all the outstanding invoices.

To my surprise the invoices were all paid within a week. It still smarts a little bit and I would have appreciated just some honesty/courtesy.
I don't wish them any ill-will but its frustrating as we had got their website to page one for most relevant searches... now 2 months later they are nowhere to be seen in Google.
So frustrating.

Onward & upwards and thanks for everyone's comments.

Thanks for the update.
It seems odd you had an apparent good call.
From a business point of view, you have a conclusion by getting paid in full.
Yes, it does feel disappointing, and the problems are now 100% theirs.
Time to move onwards and upwards.

Great to read an update, sad to hear it's not going well on your end.

fowley; My relationship with the client is deteriorating - he's querying every single £ I've ever billed him and is threatening to not pay their outstanding invoices.

My instant reaction to your story was to wish them luck / offer them a private server with private IP. I experienced a similar/identical story: the client hired my services for a webpage <-- important distinction. And then complained about emails not reaching destination, turns out they relied heavily on email for their business contacting countries in other continents. Over and over their email/domain and IP ended blacklisted (two main black list services). The process to get them out of there took 2 days (at least), it wasn't fast.

Years later, today... looking back I could easily see the mistake, they wanted a car to go to the mountains but hired average transport. I couldn't get them to understand the issue and pay a dedicated service (to isolate their email/domain and IP), and OMG I couldn't get them to understand the use of WHITE-LIST or alternate communication methods. I could easily have built a private system. Things deteriorated and I finally I wished them luck, one less client but lots of peace of mind.

The solution was easy, they just couldn't understand that kind of email consistency has a price. Still after lots of experiences I know even so there is no 100% safe guarantees.

fowley; now 2 months later they are nowhere to be seen in Google.

Clients usually don't care or fail to understand what happened, and some are too proud to fix the issue after a misunderstanding. A couple of clients failing to adhere to the terms of service went to another service provider (webmaster), their first page results vanished. One used to advertise directly on one of my websites and got great, solid results, that's gone and even so they did nothing.

I see a technical issue here and also human issues. It's part of the business.

Added: only a couple of years back I understood the difference of concept sin business when people buy a service, a product or a guarantee. Guarantee is a word, an expectation and in many areas is just an impossible reality: people want it, nobody can provide it (for real). If you try to explain and you see their lack of understanding, move on, it's a dead end. Not saying having a reliable email service is impossible, but having a bullet proof one is, some would say "it is possible if..." etc but I wouldn't sell such concept, if they can keep it up to their words then that's ok and up to them, but not up to me.