Can you retrieve deleted texts on iPhone? Restore deleted messages
If neither of the options above has worked, it is time to go nuclear. Well, not nuclear exactly but it may cost you a couple of quid, and there is no guarantee it will work.
We’ve never used any of these, but a there are some third-party apps appear to have a good online reputation: PhoneRescue by iMobie, WonderShare Dr.Fone for iOS and Tenorshare iPhone Data Recovery. Because even after you have ‘deleted’ messages they remain on your handset until overwritten, you should be able to recover deleted messages using these utilities (and others) – but there are no guarantees. (See also: How to block a number on an iPhone.)