Hi
My sister purchased iPhone 5s from Apple's website worth $849+taxes+shipping=$920. We made full payment at one click. Apple previously was not showing sim-free option so purchased iPhone with T-Mobile at full. Then, iPhone 5s was shipped to India to me. I m using vodafone sim card in it. I am able to use every facility in the phone from calls to messages, edge,3g blah blah etc.
Now i am planning to visit my sister in USA soon. I have at&t sim with me as it was my sister first sim card and i borrowed it from her.
My question to you is .... is my phone locked to T-mobile or can i use other sims in USA?