BOGO offer and ATNT chat

Hi

I purchased Atnt BOGO samsung galaxy s8+ in Jan-Feb2018. i was told i will get the credits for one of the phone.

I wanted to payoff one of the phone while making sure i still receive the credits.

Since there was a confusion on which phone i need to payoff  i contacted customer care using atnt chat.

The rep told me to pay one line out of the two. I confirmed very clearly that is this the one i need to pay off. He confirmed and i have chat transcript to prove that.

After that my request for unlock was denied.

So i contacted the customer care again and this time i was told that i had to pay the other phone. When i explained that i was told to pay line 1 the rep acknowledged that it was atnt mistake. Asked me to pay off line 2 and refunded the payment on line 1.

Post that i got credits for month or two.

Now each month atnt does not give the credit. I am forced to discuss and waste hours explaining everything to them. I have chat transcripts on my email sent by atnt to prove it is their fault. Each time they acknowledge that and say they have opened a case to take care of it. Nothing happens after that.

I am fed up of wasting so much time on this.

When in last chat i asked for escalation matrix and if i need to email the ceo for any further support, they have stopped sending the chat transcripts.

I am heavily irritated by the behavior of Atnt. I dint expect this too happen. 

What are my options for escalating this?