Well, if there is evidence in the mail, feel free to write them and call!
If you go back down, feel free to sue, print materials from the post office - then they will sing another song.
// upd
First call the support, if you are sent to put it mildly in the support, ask the elder for support, if he is just as tight, then if the hoster in your city boldly go to them! Come to them, in your hands you should already have a paper in 2 copies about what happened and what you want to figure it out! they take one for themselves, on the second they put a receipt number and a seal, and the name of the one who accepted the application. over time they must answer you.
You can print in your proof letters from the mail, and in the headers of the letters there is from whom sent up to IP.
I think they will quickly solve the problem, otherwise 1 review in nete can oh how badly affect the entire hoster!
@Palmervan if there is evidence in the mail, feel free to talk to them a tone higher than usual. Do not impose on them that you are right, but say this! If they are not stupid, they will go to the meeting and will do everything, if they are stupid, they will become even dumber.
// upd
physically removing it is still problematic in terms of backups. those. what's the matter here, if only you have lost the data, then it smells like kerosene, if 100 clients have the same universal problem, but they also fall under violation by the hoster. And if only your account - then the question will arise otherwise that they have eradicated hands and all info and dumps - and this is +1 in your karma and winning the case in court.
git
and the bitbucket.org service, there is a free opportunity to store a copy of all revisions of the site sources, which is also not bad. - Sergiks