Seriously what is going on?

Literally 4 out of 5 times I've logged on in the past week, I've found all my most recent work completely undone.

Today I logged on and I found all the 4 out of the 6 maps I put up in the library yesterday were totally missing. I checked everything and the only logical conclusion I can arrive to is that the map got backed up, and all the work I put in is gone, due to someone else's vandalism. In addition to this, a protected chest that I filled with map supplies was completely empty.

The other day I logged on and found all my work on the Nether spawn terminal was gone. This is getting pretty annoying and I think me and the other players on this server would at least appreciate some sort of notice if we are going to log on and find all our work reverted due to a back up. That, or please back up more often. This is pretty upsetting to me, I dont want to keep logging on and finding that everything I've done is gone...

Let me know what's been going on,
Manu