Um, lets see. You have a radio aka phone in a big metal and brick building at you can't get service or barely any service?

Unless there's a tower next door or the store has a repeater, most likely you are going to get little to no service. When I sold wireless phones at Wal-Mart, Cigular (GSM) would work fine because the tower was right next door. Sprint(CDMA) hardly ever worked because of the building, no local towers, and no repeaters. Even Boost(Iden) had trouble working.

Remember, the most stuff you got blocking your phone (metal, brick...), the less of a signal you will get.