Airtel — unethical behaviour of customer care agent

Address: Pune, Maharashtra, 411058

Hi,
I am user of airtel service for more than 8 years, even i started my first phone with having airtel sim. Today i got a call from [protected] at 11:11 am. Date[protected]. He was offering me some hello tune service, when i told him that i already been denied to taking that service earlier twice. That person become very rude to me as i owe him some money. He ordered me to have dnd service in my number. When i asked him that he must have some records that i already denied that service. He told me he does not have any record and again ordered me to have dnd service and cut the phone.
The attitude of that person was very wrong. It was like an insulting behaviour. I was a loyal customer to airtel, i think i should start finding some other options also.