I ordered online and picked up at att store. i came with new iphone and found out it's iphone with sprint sim card in it.

I took it back to the store that i picked up, and they told me to talk to Apple service manager..
and some long phone calls later, they think i am a scammer or something..

Att and Apple all avoided my appeal explanation.. and i don't know what to do.

I just don't know where to begin to start .

I have cleanning business, and without a phone, i can't go on my business.

help me .