I remember being on the receiving end of a complaint from a customer that their website that I managed for them was "gone". After much digging, the FTP site was completely empty. Given that only I had the access codes, it was quite strange as I hadn't touched that customer's site in months.
They were paying 123-Reg for FTP hosting, I set it up for them and they just paid it each year, so it wasn't really much to do with me, and I had backups so recovering it wasn't a big deal. But then I obviously told the customer what happened, and they complained to 123-Reg.
I got a really stroppy call from them soon after saying that I was lying, etc. etc. etc. So after much discussion, and getting through to the only guy who actually had techy access, I got to the bottom of the problem: They couldn't tell me who logged into FTP. When. From where. What was done. What backup those files were on. No way to restore from their backups. Nothing whatsoever.
So they could not disprove my "You just trashed the storage for the account, didn't you?" assertion. And they had to concede. Especially given as they had NO WAY to even say "Ah, but you logged in just before the files were reported missing" or whatever.
Shortly after, they lost all the custom anyway, but I couldn't fathom how a major web-host hosting business FTP servers at the prices they charge could not maintain the most basic of access logs.