My Caller ID and contacts think it's in China?

[jh_on_the_cape]

I bought my unlocked S4 from China through ebay. Popped a Tmobile SIM card in here in the USA and it works fine. Except that when someone calls or texts, the phone adds a +1 to the number. So it does not match to my contacts list I imported from my old phone. Also, it shows some province in China as the caller location, rather than the US State. I believe these are related. How can I get my phone to work like my old Virgin Mobile Samsung Galaxy Reverb?
Otherwise it works fine. English keyboard, etc.
Thanks.

 

[B. Diddy]

Welcome to Android Central! I believe that is usually a function of the ROM that's been installed. You'd have to root the phone and install a US ROM that was designed for that particular model. I can't give you details, since I don't have the experience--but do a Google search for "[your exact model] root ROM."