I bought a unlocked cell phone with a warrantee for replacement for my son I need to use that warranty because it broke how do I do it? Do I take the phone to Best Buy and get a new phone or do we have to call or mail it in

Take it back

Take it back. I am pretty sure if there is a warranty they gonna give you another one or at least fix it. Geek squad do that.

Take it into the store and they will lend you a phone to use until they get it fixed

Taking it to the store is normal.

I think you would have to take it back to Best Buy