Refund

I have called at least 10 times in regard to being charged monthly for a device that I returned more than 2 years ago. I have multiple recorded phone calls acknowledging the error and that I would receive a refund, but still no refund. Every time I call it is repeating the same details and spending more than an hour on the phone. I'm given service ticket numbers and when I call back to ask about them there is no details and/or they ask me to repeat the whole story again. The customer service is terrible, this is fraudulent.