hi @freedy10 welcome to the forum 
my apologies for the bad circumstances you join the forum.
first of all you should preserve the existing state - make copies (better images) from what your have (database and config, and client data). another backup of client data is important as this is your last source of the documents created after last backup!
The restore could work like this:
- restore the old data to the server
- start the server and perform Synchronising with clients after data recovery - in other words run
occ maintenance:data-fingerprintwhich will make the client authoritative and upload new data to the server
hopefully you have the server with current set of data.