HDFC Bank — Charged for Phone banking

Dear Sir,
I Mustansir Taher Madarwala have open Saving A/c in HDFC BANK A/C No.[protected] on Oct, 08.
First time when I had gone to bank to verify my proof of address that time I had ask them if there is any charges for phone banking, the bank people said that they too don’t know. Then I had called to phone banking for inquiry whether they charge for phone banking or not. when i called they said there is no such charges, I also Confirmed to Mr. Mahesh who seat on a Help desk in HDFC Bank(Nair Hospital-Mumbai Central).
But When I received the Statement in March I was shocked to see that they had charged me around 500/-and till date they still charging me .I am unable to understand that why I will call there if I can access my net banking account from computers only.
So please help me in this Matter.