Okay so I bought this unlocked slvr l7 phone from ebay. Once I got it I took my mother's nextel sim card to test it out and I could swear that it worked. Though after I started using t-mobiles prepaid sim cards it stopped funtioning. I can't get it to connect to a network with my mothers sim card. I have started reading some post, and to what I understand, nextel uses a different type of technology and not gsm. So It could not have been possible for it to have worked with my phone. But I remember that it did. What can I do? Could anyone kindly assist me with this problem?