Airtel — Continuation of broadband connection without consent

I raised disconnection request with Airtel broadband in April'22. The customer service representative told me that we'll process the request and will give cashback/waiver in final settlement if applicable. I said fine but close the connection asap. The next month bill came but it got nill on it's own. I thought its a mistake from their and got rectified on it's own. But in June the bill came again and this time i called them and they said the connection was active as i accepted to continue connection by getting the waiver. And now they're telling me continuously to pay the dues. At the time of feedback call they didn't mentioned that cashback/waiver as offer for service continuation. They did a fraudulent activity by not mentioning this at that time and now calling me constantly to clear the dues. I want Airtel to cancel the bills and give me no dues remaining certificate as this is impacting my credit score.