Hello Textsdisappeared,
Welcome to Apple Support Communities!
We understand that you want to know how to recover messages that disappeared. We'd like to help!
Were these messages texts or iMessages?
If they were iMessages, have you checked to see if you have available iCloud storage? You can use the steps here to check: Check your iCloud storage usage online or on any device
If they were SMS text messages, we recommend reaching out to your wireless provider for further assistance. You can learn the difference between message types here: About iMessage and SMS/MMS
Let us know if you have any questions.
Take care!