iPhone 4S - MMS works for sending but not receiving - ???

[conqst99]

Hi All,
Wife just got her 4S last Friday (32 gb, white) and we've noticed that she isn't able to receive any MMS messages that I'm sending her. Although she can send me MMS messages and I can receive them. I looked thru the settings and believe that everything is set up the same as with her 3gs. She just started an AT&T commitment plan. Any ideas? I checked and the MMS messaging option under Settings / Messages is turned on. And the Cellular Data is turned on. I know from past experience on my ip4 that if either of these is turned off, you can only get SMS.
Dave

[conqst99]

UPDATE: Forgot to mention that this may be the problem. She was using Tmobile on her JB'd & unlocked iphone 3GS with the data plan. When I restored her backup from that phone onto the new 4s (contract with AT&T), I'm guessing that the originally programmed settings from the guy at the Apple Store were overwritten when the old 3gs backup was restored onto the 4S. Does this sound about right? If so, I would need the proper settings for the cellular network info on the phone for use thru AT&T so that MMS will work for receiving. Weird thing is that if the data settings are still set up for tmobile, how can the web surfing and sending of MMS work? Any help would be appreciated! Thanks.