No resolution on billing query

I am highly annoyed with Vodacom, they charged me exorbitant amounts on my data contract, I went into the Vodacom shop in Kolonade explained my grievance which she promised to log a dispute for and provide feedback in due course. I waited and NO FEEDBACK!!! Phoned the store and was given a reference number to make my own follow-ups. I phone Vodacom (a tedious exercise on its own because the call centre agents are beyond ***********) numerous times and finally getting assistance, I'm told the query/dispute is closed but NOONE HAS GIVEN ME THE OUTCOME!!! I had to log another query which means MORE waiting while all this time my device is hard locked, I am unable to use it but continue to be billed. HOW IS THIS EVEN LEGAL????? I am so disappointed in the service generally and this ******** act of charging amounts on my account but unable to tell me WHAT EXACTLY you claim I used this data for! I want to cancel my contract but unable to until the issue is resolved. FRUSTRATED!