Hi I am new to the site. I just received my Unlocked GSM quad phone that I purchesed on ebay. It is a CECT Phone. It has led lights that flash with the music and it has yamaha sound. That is the only information I can provide. It is a dual sim phone but can work with just one sim card. My problem is I insert my sim card which I have through at&t wireless and it says that I have no service. I can't figure out what I am supposed to do. From everything I have read I should be able to place the sim card in it and then turn it on and it should run. Any suggestions?