Airtel — Airtel charging for nos with 1860

In April month bill I found an additional charge of Rs. 27 plus taxes against Voice special numbers service availed on 29th March. As per my bill plan all voice calls are free. They have charged for calls starting with 1860. In bill plan this was never mentioned it will be charged. Now a days most of the banks & other companies give customer care nos starting with 1860. How a customer can connect to banks or any other company customer care if airtel is charging customers for nos starting with1860.

I want the charges to be removed from my bill as soon as possible and Airtel should stop indulging in such practice of charging customers for numbers starting with 1860.