terrible service & incompetency

Someone at Vodacom wrongfully and without my consent cancelled my handset or contract and now expect me to pay R 4812 before the end of the week. I did not give this order and seeing that all their calls are recorded I would like to have proof of were I gave instruction for this to be done. I will not pay for someone else's mistake. I have been with vodacom for many years and received excellent service. But this issue has been going on for 2 months now and I am fed up. Please help me resolve this