Motorola ROKR Z6m

I've had the rokr for a few months now. It was working perfectly, until a few days ago. I had it charging over night, as always, and when I turned it on the next morning all of my contacts were missing.

I thought it would fix itself and just added some of them back. Until today, when the few I had re-added disappeared again... I really like having contacts, it's a pretty nice feature for a phone, so does anyone PLEASE know how to fix this issue!