I ported my number to AT&T and when I got a bill asking for next months service, it put up a red flag. I went online and looked at my past bills. My first bill clearly states that sprint bills one month in advance and shows next months portion as well as the price for my phone, activation fee etc. After looking at my 2nd bill, it shows the bill period for the last month (the month I already paid for). I had to call sprint and talk to several different people about this before they canceled the last bill they sent me. I believe I should actually be credited money back for paying for a month of service that I didn't totally use. Just a heads up to look at your bills and make sure you aren't paying for an extra month.