In December, 2013, I paid my Verizon bill with a phone rep. The representative mistakenly credited my $134.65 payment to someone else's account.

I understand how the mistake was made: The person whose account was credited used to live at my address and, for now, we do have the same last name. His bill is in default because he doesn't feel like paying it.  I can show the withdrawal from my bank account and I can show the credit on his bill.

I have called Verizon and engaged with phone chats multiple times. Twice, I have been promised my refund. Most recently, I was promised that the $134.65 would be refunded to my credit card by January 10, 2014, but this has not happened yet. Meanwhile, it is February, 2014, and I am still deducting this amount from my bill, so it looks like I am not paying my full amount due. I am very unhappy that this situation continues to drag on.

How can I get my $134.65 refund?