Had issues with channels that I was not receiving....

Had issues with channels that I was not receiving. Returned the cable box THREE times within the past 6 months. Still not working correctly, so they suggest a service tech comes out to see what going on. They tell me there "MAY" be an $80 service charge "IF THE PROBLEM IS ON THE HOMEOWNER'S END" Fine - I understand.
The service tech shows up on a Sunday and finds the problem is an old cable and he changes it. Great. Everything works now.
***Here's the problem:***
The tech tells my husband and I, and I quote "SINCE I DON'T KNOW IF THIS IS A CABLE WE (as in THEY, THEM, CABLEVISION, OPTIMUM lalalala), INSTALLED OR YOU INSTALLED YEARS AGO, I'M NOT GOING TO CHARGE YOU FOR THE CALL"
Fast forward to our bill arriving yesterday. And VIOLA! Yesiree! There is the $80 service fee on there! SO I call and explain to no avail. Even spoke to the supervisor. He keeps saying if the tech has to change a wire, that's considered a service charge. I keep telling him what the tech said and I said call the tech yourself! I WILL NOT pay the fee for something I was told by the repair guy. I received no receipt, nothing. The supervisor says they cannot be held responsible for what the tech says. REALLY?? The crappy supervisor would not budge on refunding a mere $80 to a long, long, long time customer. I told him it's not MY fault - you take it up within your company and the technician! So angry right now, we are so ready to cancel and move on...