Airtel — internet service wrong bill generated

Address:

Mahagun Mywoods, 16C, Greater Noida West, Uttar Pradesh

In april i tried reaching customer care, but no one was available due to lockdown. Finally, i got a call from their own customer care as my advance recharge was going to get over in may. I requested to put my number in safe custody, she told me that she has generated the request and a call back is arranged, i never get any callback. I was not much aware of the process so was not able to do it myself from the site or mobile app.
Once again in a few days, i got a call and i requested the same, they again said to arrange a callback and explained to me the whole process. I do not get any callback, neither do they give any reference number.
Meanwhile, my bill got generated, i started getting calls for bill payment. From everyone, i asked to put my number in safe custody. One of them in fact took around 30 - 40 minutes and said that my number is not in safe custody and nothing needs to be done.
But no change happened, i continued getting daily calls for bill payment. I then searched the internet and learned how to add numbers in safe custody and tried to do that, but it is now not allowing as the bill is generated.
If you see the data usage, i have not used it from mid of april.in may, i moved to my home town and it is even switched off since then.
This is just harassing a customer and unethical.

Resolution needed - cancel the bill that is generated and put my number in safe custody. I should not get any calls for bill payment or to renew my service.