Default Text messages dissapeared after removing sim

I know this is an android forum but im hoping someone can help with a problem I have with a motorola krzr.

The phone had lots of stored text messages, and I removed the sim and temporarily put a new one in to copy contacts to, then put the old one back in.

Now all the sent and recieved text messages have dissapeared. Im not sure how this happened as I didnt do anything to delete them.

Is there a way I can get them back?