Worst Service provider Airtel

I had requested for the cancellation of wifi services of Airtel connection and had removed it 3 months ago, the Airtel team after fighting with them multiple times on phone they cancelled my connection and also had taken the router from my place, Till date I’m getting large number of calls from Airtel team asking if I’ve given my router back or not, Do they not have a proper tech team where they’ve updated the status of device recieved or not, I’m totally annoyed by this every 2 days I’m getting a call from Airtel and it’s the same that they’ll update and nothing from their end. How do such a large company handle the customers? Customer experience is a joke in India I feel that and there needs to be strict laws related to consumers.