I want to restore my deleted messages on my iPhone 4

See this discussion...

https://discussions.apple.com/thread/3937870

From the More Like This section on the right.

hello if you are still stuck try http://http://www.enigma-recovery.com/smartphone-recovery-pro2/ they was very helpful and i got back all my deleted messages

If the phone was backed up (to iCloud or iTunes) before deleting, restoring the backup will retrieve them, but you will lose any messages on the phone after the backup was done/

iOS: Back up and restore your iOS device with iCloud or iTunes