Had a fairly similar situation a few years ago.
We provided and hosted the ticketing website for a prominent Train operating company, and late one Friday night the website disappeared off the internet.
Turns out the TOC still controlled the company domain name on which the site was hosted, and they had steadfastly ignored all the renewal letters and emails from their domain registrar, so the registrar suspended the domain.
Come the Saturday morning, and a veritable shit-storm of abuse is hurled at us from just about every senior member of the TOC staff, threatening all sorts of reprisals up to and including legal action.
They were slightly hampered by the fact that the same domain was used for all their company emails, but they still blamed us anyway.
When we tried to explain that it was out of our control - and in fact only within their control to fix it, we were met with demands - not requests but demands - that we do something about it immediately.
So, given that our agreed support contract was only for office hours, Monday to Friday, we chose to ignore the increasingly desperate threats and cajoling for the rest of the weekend.
On Monday morning I rang the TOC's grandly named "Head of Technology" and slowly and carefully explained the situation. Again. After further investigation, it appeared that the member of staff responsible for managing the company domains had been "let go" and had been the only person who had the log-in details for the domain registrar account.
It took until the Wednesday afternoon before the site was returned to normal operation.