Consumer Redressal

I got a call from vodafone on 28-03-2013, cross selling me an upgrade plan. The girl calling explained that I can upgrade to a plan where after I exhaust my 2GB data usage of the 3G 450 plan that was already active then, I can avail of free data usage but the speed will reduce to 2G instead of 3G, after I exhaust the limit, without any extra cost. She told me this service is free. For which I said okay. And accordingly thinking that I have free data usage I extended my limit of usage. Next month when I get my bill there is a charge of Rs. 1050 over and above of Rs. 450 my monthly rental for data usage. I raised the matter and the customer service guy (always pathetic) says this is a paid service and I have been charged correctly. But when I tell him that I was not informed about the charges they turn a deaf ear on me. I have even written email to nodal desk, customer care and also lodged complaints at vodafone gallery. The last call I received from vodafone nodal desk they confirm they will enquire as to who gave me incorrect information and get back to me. Its a month now I have not received any revert from them. Plus the company is harrassing me for making the additional Rs. 2100 payment. Please help me in punishing vodafone.