I am on the 3 network and have a nokia 6500 slide my friend is on T mobile and can send me texts and calls me with no problem,but she cannot send me mms her phone states mms not sent number not available... !! Any ideas ? Thanks.
She probably needs to obtain a different message centre number from her service provider to relay her MMS messages. Tell her to have a look in her MMS message settings if there is a message centre number.