Your text messages could be in a few different places... Hopefully they did get backed up. They could be saved in Samsung Cloud or whichever Google account you logged in with (Google Drive.) So if you set up backup/restore, those are the two accounts that backup to a cloud based program. If they are there, restore the last backup. The last place that maybe they could be hiding is in Starred messages or on the SIM. Not sure where else besides being deleted.