text message problem

i have been having problems with my text message feature, i can send text but not receive it. This has been going on for about a month now. I went to my service provider and they had no clue. I had cyanogen mod 6 on my phone (htc hero from cellular south)  when it happened and had been running the system for several months. I did a factory reset, a cache wipe from the recovery boot menu, reinstalled the program, then updated to cm7 but i still can't receive messages. I was thinking about going back to the factory htc sense program to see if that works but i love cyanogenmod. Does anyone have any suggestions?