Charged over $1600

In May I switched from Verizon to Xfinity mobile. It was done on a telephone call when I was changing my cable plan. During the call I told the agent that I had a new plan with Verizon and I was paying for the phones for the next 3 years. The woman said that they would cover the cost of the phones from Verizon. I got the new contract from Xfinity Mobile and Verizon closed my account. In the process, Verizon charged my bank account over $1,600 for the phones that were still unpaid. I have called Xfinity four times in the last 2 month and each time I am told that the situation will be handled. The first time I was told that refund would come to my bank account, and 3 weeks later nothing was there. I called back and was told  that I would get prepaid cards in my email, 3 weeks later there was nothing. I called again 2 weeks ago and was told it was going to the tier 2 team. Still nothing there. There has never been a response from Xfinity from any of these calls. Each call takes at least 45-75 minutes. There is no number to call for dispute and I have to continue to start the process over again with another call center.   The new person cannot ever connect me with a supervisor and can't help me each time.  I am told that it will be handled and it never has been. What can I do? This is wrong!!