“Datafile.edb.old” solution for restoring deleted library DOES NOT work. Can someone help me???

Recenty my entire library was deleted, without a reason. I tried the “datafile.edb.old” solution multiple times but it just won’t work. Maybe because I opened/closed RB to many times. I also don’t know if my datafiles are corrupted or something like that. Could someone please help me recover my library???