I was on my server earlier today after having been away for a few months due to issues with my computer. Spent hours on saturday building a new, much faster PC, and after getting everything setup I was excited to finally be able to play with my friends again on my massive server that I've spent several hundreds of hours on over the past half a year, full of massive complex builds and dozens of automatic farms, redstone contraptions and an enormous automatic item sorter. I was on the server earlier today, just seeing how nice it looked with shaders (which I can finally use now that I have a new PC) and fixed up a few things.
Left to eat dinner and got disconnected for being AFK, as expected. When I got back, I waited an abnormally long time for the server to just finish "Saving..." (probably 15 - 30 minutes) and when I got back on the server, I see a completely new area that I don't recognize, in the middle of a random forest, with nothing familiar in sight, as well as an empty inventory and no OP perms. After going to the website to give myself OP again, I confirmed that indeed there was a new seed and the entire world, which I had spent so much effort on, had been completely reset.
I know I should have saved a backup at some point, but this is completely unacceptable for a server host to completely delete a server without warning or notice. If there's any way to recover it, I'd appreciate it so much, but if it really is permanently gone, I will NEVER use Aternos again, and I'll strongly advise against anyone else using it if this is what could happen to any server on this platform at any given moment.