I have 2 iPhone 5s on Att. My contract is ending shortly. The service I get is bad. I can be standing next to the other person on my account, text or call them, and it won't go through for hours. I had an small emergency that I needed to contact them for and had all calls go to voice mail, which they did not get for hours. Initially we did not live close and this was not an issue. So, I know I have to be paid up and contact ATT to get unlocked, but what happens after that? I have 2 sims from T-mobile that I would like to activate and try with the phones, but will my Att account end when I unlock or do I still have to cancel service? Will the phones still work on Att after unlocking, in case I decide not to go with T-mobile? Any help is appreciated. (Also, I will most likely upgrade to iPhone 6s' in the future, but I don't want to be locked into any contracts right now.) Thanks.