unauthorised charges by vodafone

Hi,
I am facing similar issue where my account has been deducted with rs75. When i contacted the support i was informed that i have downloaded some application and have been charged for it. I have checked my download history there no such download which i have made.
I contacted the vodafone support and the only thing they say is i have been charged for the download, but they are not ready to listen and understand that i have not downloaded any such application. Waiting for the backend team to call amd hoping to get a positive response atleast from them.