Messaging remembers previous carrier for MMS messages on wife's text messages

[martin1833]

Both my wife changed carriers from ATT to T-Mobile last year. We transferred our phone numbers to T- Mobile. When I receive a text message from her it displays ###-###-####@mms.att.net. If I respond it never gets to her because she is now on T-Mobile. The same thing happens when initiating a text from my phone. It shows up as att.net and the send fails. I've tried removing her contact from my phone but it still does not work. Somewhere in the phone it is remembering the old carrier. I have even deleted all my contacts but no joy. Does anyone have any suggestions? I am running Android 2.3.6.