600+ Cable Bill I Can Not Get Resolved

Gone for 4 months and went to store to have service shut off. Receive a bill 1 month later called xfinity and they said it was still on but was told they would shut off and credit me. Following month receive another bill and again I was told it’s still on but they will shut off and credit me. This happens third time same scenario. Then they told me to go to a store location and I do then I’m told I have to go to location I originally went to. Have my daughter go(I’m in a different state) and she is told there’s nothing they can do and we need to call. I have called and a lot more than the 3 times and now I have a 600+ bill.