I have a DEXT(LA version) model MB200, system Blur_Version.2.1.5.MB200.T-MObile.en.US and kernel 2.6.29.
Everything was fine until a pop-up: "The process com.google.process.gapps suddenly stopped. Try again." starts to appear every 30s. After this, SMS messages don't arrive. Now my google account was erased of the phone and I can't add again. Because of this, all my contacts gone.
Try clearing some cache's. The easiest way is to download a cache cleaner from the market. (I'm using Cache Cleaner NG - cleans every 12hrs) I think cleaning caches is important because it frees up space that is needed for the phone to run correctly. When I first cleaned it, it freed up about 20mb of needed space. And that is space that the phone mite of needed before your problem happend. I'm not saying it will fix your problem but it will help prevent future problems.