- Check to see if they are in the Recycle bin of the Messages app (if enabled). If they are then you can restore them. - Potentially they could be within a Google backup or Samsung device backup. If you check under settings-> accounts -> backup then you may be able to restore a previous backup
You could use third party software on your PC that has the ability to recover SMS messages (Google this), connect the PC to the phone, run the software and that should easily recover any lost text messages 🙂. Hope this helps! 😊