All My Data Are Gone!

I just noticed that my next cloud folder is completely empty, the whole folder has disappeared.
Except the 3 files :

I did not delete the file of course, it disappeared by itself.
I think I have a copy of all the documents present, but it is still annoying
The last time I used next clound it was 8 days ago, and everything was fine.
I even have on the “activity” the history of me creating folder and adding new file and on the history we don’t see a “delete command” anywhere so i don’t know what all the data get removed like that with no reason. I would like to recover my files because they are important.
Even on the option “deleted files” there is only the file i manually delete in the previous month but no trace of the removal of the entire file.
Thank you for your help in advance.
I hope that we can find a solution!