Hello,
Generally, the deleted or lost Samsung phone files, photos and videos are often able to be retrieved back when they have been stored well in advance on the phone Micro SD or SD memory card.
So, in your case, if you do have saved at least one copy of lost contacts and files on the phone memory card, you can also go try Samsung phone memory card data recovery freeware to recover deleted messages and files from your Samsung phone flash memory card.
Read more here:
https://www.icare-recovery.com/howto/recover-deleted-text-message-sms-from-android.html
Hence, what you are supposed to do now is to search and launch a proper data recovery tool to take desired information back.
Hope you can learn an impressive lesson to save phone data backups well from now on.