My sequences keep disappearing, what do I do?

[DropDMike75]

So (at least) 4 of my sequences disappeared one day without warning or reason, and I don't know how to stop this from happening again. I don't know who's doing it, but I've lost weeks of work, and I'd like to not lose months of it. I seriously need someone's help, if you have an idea to stop this from happening PLEASE let me know ASAP. The songs I lost don't seem to have a reason to be reported and/or deleted and I'm scared of losing more of my work.