recovering deleted text messages

This is going to be tough. You will not be able to retrieve any deleted texts unless you restore your iPhone from a backup that you may have created. The other thing is that if you restore your iPhone from a backup then your texts will only be as current as the day and time the backup was created. 

If you choose to restore your iPhone from a back that you may have created then here is how to do it-->>Restore your iPhone, iPad, or iPod touch from a backup - Apple Support

Good Luck.

Axel F

Restoring from a backup is all or nothing, there is no nick picking on what to restore back. Yes contents that was last backed up is restored to your phone and whatever wasn't included in that back up won't be on that phone like new data.

you'll need to decide if this message thread is important enough for you to restore from you backup.

No you can't view what was last backed up, you can read here what is backed up What does iCloud back up? - Apple Support

Do you even back up to icloud or itunes?

From here Restore your iPhone, iPad, or iPod touch from a backup - Apple Support

but if you use this Keep all your messages in iCloud - Apple Support its gone.