Defective Blackberry

guys, I am curious, as I bought bb 9700 out right (without contract) under my friend's account. I was wondering can I walk into any t-mobile store with the receipt and exchange for a new one? or I have to bring my friend to the exact t-mobile store I bought it from?

Thank you so much for all the replies.

friend into store or have friend call customer service.

Yes have your friend go into the EXACT Tmo store you bought it from and as long as they verify its defective they should exchange it.