The phone stops receiving text messages after its been on for several hours, i can send text messages all day long and they are received by the people i send then to. i can't get any messages back unless i power the phone down and wait several minutes then restart the phone , then all the messages that have been sent to me start coming all at once, the phone will work normal again for several hours and then stop receiving text messages again, this is the third phone , same model that has done this, it will receive mms message just fine , at&t tech support has no answer and have had me try different text message settings and nothing helps at&t just sends me back to store for a replacement,each phone stops working normally within several hours, we have tried a new sims card, still no help , if i put my sims card in the 10 dollar walmart phone it will work fine . any suggestions ? thanks, steve schmitt {sgh a 777} 1 green , 2 blues