Airtel — calling a toll free number declared by indian companies are charged in my bills

Address:

Ahmedabad, Gujarat, 382481

Using airtel numbers since many years, and recently have checked detailed bill and found that i was being charged to call on toll free numbers of axis bank card lost, gtpl complain number, tatasky helpline tollfree numers and list goes on and on.
For few i have been charged for international calls charges as per their logic i have prefixed 00 before the number so it went for international charges. Which is very stupid.