If you use iPhone and have changed your mobile carrier, you may have noticed that phone numbers for received messgaes are not being matched to your saved contacts anymore (as I did today).
To resolve this problem, you need to update your carrier through iTunes. Connect your iPhone to iTunes, and once iTunes has started up, it will ask you whether you want to update and configure your carrier. Select yes and let it finish the sync process. Once the sync is completed, you’ll find that phone number are now matched to contacts.
If you see some of the numbers are still not matched, open Contacts and click on refresh button in top left corner.