Hi.
I had this problem today. Here's what I've done:
1.- In contacts application, export all contacts to SIM card (my SIM was empty, so I had nothing to screw)
2.- Then I deleted all the contacts.
3.- Reboot.
4.- After reboot, in contacts application I imported the contacts from the SIM card.
Now I have no merged contacts because they're not allowed in the SIM card, and the long names are also truncated, but I can see all my SMS's.
Regards.