Samsung Mesmerize won't send MMS?

I have a Samsung Mesmerize & the pic messaging isn’t working. The short cut keys also stopped working so I got a new one through insurance. I have had 3 replacement phones sent to me in less than 3 weeks. I can NOT get pic messaging to work. I have done battery pulls, sd card pulls, factory resets, have had my carrier reset my towers, reprogrammed the phone, put a new sd card in & still NOTHING. My wifi & Bluetooth are off. My data is enabled. The firmware & software are up to date. And my carrier (US Cellular) has no data outages. Are there any other things I can try before I have to go into the store or get ANOTHER replacement?