Vodafone Wrong downloading charges in my bill

I am a Vodafone Postpid Customer in Chennai using 2G data plan of 199.
Vodafone has charged me Rs 150/- for downloading “mobilart_valuepack” for Rs
50/- and “myplex_ap_100” fro Rs 100/-
So in all they have charged me Rs 150/- for downloading a stuff which I had
never downloaded.When I called their Customer Forum for explaination they had
no proper explaination.