So I bought a used Samsung Highlight for tmobile through a trusted ebay seller (phone was to be in 100% working order). I took the sim card out of my old tmobile phone and put it in this one. It powered up just fine and everything works, but there is no signal, and it cannot find the network. So I talked to tmobile tech support and they had me reset the phone and do the usual things that I had already done. It still doesn't work. Do you all have any other ideas?