I am in the same situation as you. I purchased the A51 from Amazon so I could use on XM. They will not let me use it. Don't believe any of the reps that tell you that the technology is not the same. It is. XM has specifically blocked the A51 (I think it is all A series phones) from being brought into their network. The reps cannot get past the block in their system. XM wants to force you to pay for the phone through them and it is more expensive. In addition, they lock their phones so you cannot take it elsewhere until you pay it off. That way they lock you into their network for the term. It seems like they are targeting the group of us who would want to save money on mid tier phones and purchase them at a good price. I had a supervisor send a request to open it up to the A51. But who knows where that request was sent to.