Well, u bought an iphone 5 on ebay. I asked the seller if it's clean esn, but he only told me that I'm just gonna need a new SIM card and that the store has it. I'm on a post paid plan. I'm just wondering since the seller said I'm gonna need a new SIM card if it's probably prepaid and some people online said that you cannot do prepaid to postpaid. Can I still activate the phone as postpaid?