Vodacom charging me unrecognized *****ulent charges

Vodacom charged me unrecognized charges, when I asked them they say I made purchases on Google play, which is false, I did not buy anything on Google play, and as a result my account is in arreas because of something I know nothing about, I tried reporting it to vodacom customer care but they don't care even failed to respond, my worst experience with vodacom contract.