We had unlocked and switched our iphone from at&t to tmobile. Just going through that process was a giant headache. After making the switch our iphone was unable to receive and make calls half the time. The employees over at the val vista outlet location told us the problem was due to our phone only having two antennas and that we pretty much needed to buy a new phone to solve the problem. Needless to say they were very rude over there. Long story short, went to this corporate location, spoke with Brandon, best decision ever. He told us we might just need to switch to a newer sim card and wala! the phone is working great. By the way we got the first sim card from the rude val vista location. Thanks Brandon for talking with us and trying to solve our problem before turning around and trying to sell us something we didnt need. Now we can still buy christmas presents!