I'm doubt whether you did the proper operation. Here are the professional process:
From iTunes backup:
1. Connect your iPhone to the PC with which you sync it. iTunes should open (if not, open it manually).
2. You should see your iPhone in a box, top righthand corner. Select it.
3. Now choose 'Restore backup'.
4. All the data you previously backed up will now replace the data on your phone. It will take a few minutes. As long as you haven't backed up subsequent to deleting those text messages, they should now appear on your phone handset.
1. Login to https/icloud.com
with your Apple ID and password
2. Click on Text Messages (if it isn't there your messages haven't been backed up).
3. If it is there searched the messages to find the ones you need.
4. Now go to your iPhone and choose Settings, iCloud on your iPhone.
5. Turn off Text Messages (or ensure it is turned off). I know this sounds counter intuitive but stay with it.
6. You'll see a pop-up. Select: 'Keep on My iPhone'.
7. Now turn back on text messages.
8. Tap 'Merge', and wait. After a few minutes the deleted text messages should appear back on your iPhone.
If methods above still cannot work for you, another good way is to put your problem on this facebook: iPhone text message recovery where you can get the professional and quick reply.