Airtel — vas activated without my consent

I recharged my airtel mobile number with rs. 20/- and had an updated balance of rs. 15.45/- on 17 november, 2017. Then, they activated vas, videopindw of rs. 15/- without my consent! This i found out while trying to call and hearing that i don't have sufficient balance! I want my money back. I did not want this vas activated! Also, when i tried contacting customer care on 121, the automated voice told me that it is an invalid number! Please take action.