Holding my phone hostage

my son got on his own phone plan and went into the Pasadena xfinity store to ask what he needed to do. They told him if he paid off his phone it would automatically unlock and he could get service anywhere. So he did that and the next day (12hrs later) he got service with T-Mobile and they said his phone was not unlocked so he needed to go bk to the Pasadena xfi store and ask them what the issue was, the xfi store said it would be unlocked the next day. 24 hrs after that it still wasn’t unlocked so he went bk up to the store and was told that he couldn’t unlock a device without the primary account holder there. I went up there myself and was told they put in the request and it would be unlocked in 48 hrs. It’s now 3 days later and still not unlocked and customer service has already disconnected my call once when I asked to escalate the situation. We have been to the store 4x now and I followed every instruction they gave me at the store.