Airtel — Harassment by Airtel Spam Calling Hooligans

I disconnected a connection from airtel over 3 months ago, [Feb] by calling customer care and letting them know I was done with their service because it kept disconnecting randomly, the technician said that they will do whatever it takes to fix it the next day, when it wasn't done the next day, I told customer care, I want to close the connection, they acknowledgeded the request on phone, they initially tried to tell me no sir are you sure, if we raise cancellation then it will negatively affect the technician's job, I was like I dont care man I still dont have internet, I am not paying for this, they reluctantly agreed, I got ACT same day installation and moved on, now I am beginning to doubt that the request for cancellation was never raised to protect the technician's fault for not fixing my line

Now I keep getting a call from random airtel hooligans claiming that my connection is still active and that I need to pay my lapsed bill

Who's at fault here? me? for not taking in writing that I have indeed closed my connection? if it helps, I contacted Airtel through that thanks app they have so I am pretty sure I can get logs of my conversation saying I closed it with them, but the conversation happened on phone and I can't tolerate the hooliganism, everyday 10-20 people random numbers message me saying you need to pay bill but as far as I am concerned I cancelled legally by calling airtel customer care, as a consumer, what else am I supposed to do?

I am extremely fed up of this and need help, it is negatively affecting me dealing with this nonsense everyday

If you believe this is my fault, happy to pay and move on, but no one replies to the emails I send customer care, different hooligans keep harassing every day, no resolution is in sight

Request help/support of any kind