Im an Airtel customer for last 5 years and I found its customer care to be pathetic, they are cheaters. Following are my 2 bad experiences.
When I changed the modem few years ago, I paid Rs 1500 for the wifi router, but they kept charging Rs 99 every month as rental for the router. They said the router is Airtel property and they had no proof for my purchase but I had the bill with me. I had to fight with customer care and it took 3 months to get the amount refunded
Without my knowledge I was charged Rs 99 per month for PC secure anitvirus subscription for 8 months. I remember one customer care executive calling me for PC secure and I declined it straight away. I never installed nor downloaded PC secure but I found after 2 months that Im been charged unnecessarily and asked them to cancel it. They did not cancel it, I came to know about it little late, only after 8 months. When I spoke with customer care they said they could not find any reference for the previous calls that I made and PC secure subscription was not cancelled. This time I wanted an email communication from Airtel for the cancellation and after some argument they decided to refund some amount.
It was a good lesson for me as well. Ever since I opted for ebill, I never used to check it every month, so these mistakes went un-noticed.
Only good point regarding Airtel broadband is that I found their connection to be highly reliable. I only had 2 disconnects that Im aware off in the last 2 years. I work from home most of the time so I need a reliable net connection. Those 2 disconnects got fixed within 30 mins