I'm sorry you're having trouble retrieving your MMS messages. I'm here to help.
I've thoroughly researched this and found no reported known issue of this happening on the Samsung Charge.
You mentioned all the troubleshooting steps you've taken and I just wanted to congratulate you on a job well done. You've done all the trouble shooting and at this point the next step would be to perform a hard reset on the device. This will completely wipe your device clean and reset to the manufacturer settings.
Please make sure you save any data onto your memory card before performing the hard reset. Once you are ready to perform a hard reset click here for step by step instructions.
If you are still unable to view your MMS messages after performing a hard reset please let us know for further assistance.