Ah, the company that - what, 20 years ago? - insisted that I had deleted a client's entire website by FTP and told my client that. When. in fact. they'd lost all the files, didn't have backups, and didn't even keep any kind of FTP logs to corroborate any kind of activity anyway (it took a while but I eventually got them to admit that).
Somehow the files just disappeared.
"Must have been you" - why would I delete my own (long-term and well-paying) client's website randomly overnight (and not just a broken website, but an entirely empty FTP) and then have them phoning me up on a Saturday afternoon screaming at me because nothing was working? Also: I wasn't anywhere near a computer for that day and there's been no updates to the site necessary for several weeks. (Also, I reuploaded my backup within 10 minutes of being told, and everything started working again).
"Must have been your client" - nope, they literally didn't have the password to it. They bought the service through me, and because they knew I wouldn't delete everything randomly and didn't want to disturb me first, they went straight to the supplier... who then tried to tell them that I'd deleted everything randomly.
"Must have been hacked" - I'm literally the only person with the password, at all ever, in any way. It was 20+ characters long, randomly generated and written down only in one place (and I had to manually enter it each time because I don't trust password managers). And if that's true, you'll have logs of rogue logins, right, before you start telling my client that I deleted her website? Because in the same conversation I was told that I couldn't now reset the password - so can you tell me how I'm supposed to secure a site that I can't change a "suspected" compromised password for?
Eventually, I got them to admit they'd had a backend storage failure but didn't think it had affected anyone, but boy did it take some pushing (and one of the few times I've ever recorded an MP3 of a conversation on a phone because I just didn't trust them not to tell my client something else).
After that, we transferred all that client's - and my other's - domains away from 123Reg.
Weirdly, my new employer uses them. Fortunately, they are literally just the domain host, so MX and A records are the only thing I care about them supplying.