Bharti Airtel (Broadband) — I had already discontinued by clearing all the dues before the bill date but still they are asking me to pay an extra months bill

I had already discontinued my broadband by clearing all the dues before the bill date but still they are asking me to pay an extra months bill. Which i'm not aware, i had paid the bill the same day and then requested for the discontinuation and my due amount in the app was zero, now after somany days they are calling me and asking me to pay again for a month which i didnt use. First of all i had moved out of my old residence in the beginning of month and thats why i had to discontinue since airtel was not available in my residence location.. Now they are disturbing me with the frequent calls. This is my airtel broadband user id[protected]_kk