Vodacom Bad Service , Bad customer care

I received a company phone and had to transfer it to my name, the end of that month I received a huge bill and was charged for the previous owners calls and data used. I cancelled the debit order as it was over R3900, my phone was blocked, After phoning various departments in Vodacom I got a reference number and my phone was unblocked. I never received any feedback regarding my query and once again my phone was blocked. Trying to explain to them that this was not on my name is like impossible, I did not use the phone and was billed for somebody else's usase, they just do not understand and sending me from this deptment to that department - with no luck - how do I go about this now.