Bought my mom a new 6S+ off swappa, looks like a legit high volume seller and phone is obviously new in box. Phone fails AT&T unlock with reason Unfortunately, your unlock request was denied because:Your device is currently active on another AT&T customer’s account. Seller swears it isn't tied to an account and won't be blacklisted. Claims all new phones are denied unlock for three months. Is this true or should I return it?