Complaining to support because they can't fix a file isnt really a good route- its not going ot get the file back.

you could try the Project repair kit (use google, a few places that can supply it)and you my get lucky. Sometimes it works, sometimes it doesnt, and theres no way to tell how its going ot go.

Do you use the backup feature? I dont find it very useful, but sometimes it can provide a recent save.

finally, how often do you save files? I tend to save every so often- either after a time or after making a major change. Its easy enough to save as different files- project001, project002, project003, etc, and if something goes wrong the amount of work lost is minimised. you can always delete saves if space is a problem, and just keep the last few in case of errors.