***** on account

I have a Vodacom contract (for many years) Four months ago, strange billing on my account came through (debit order). When I investigeted, 5 new cell phone numbers were opened to my account. Within 5 days, more that R17,000 of costs ran up. Calling Vodacom, the numbers was "blocked", but after 4 months now, the ***** is still not cleared from my name, and I get 10 calls a day from Vodacom that I am in arrears and I am threatened that my number (note number, my number) will be disconnected if not paid. What to do?. Every time I call, it is still under investigation. Totally not acceptable !