Poor customer service

Last year December I upgraded my cellphone contract online with vodacom, I was advised by one of their call centre agents that an iPad mini could make voicecalls I then placed an order, upon receipt of the device I then requested vodacom to reverse my contract I logged a call with them on the 19 December 2014, the devised was returned to vodacom on the 22 December 2014 and was further advised that it takes about a week for the reversal to take effect. I hv been following up with vodacom since then and everytime I get a different reference number, on the 30 December I was billed according to the upgrade that never happened. On the 19 jan I was advised that my request is still pending, on the 25jan I was incorrectly billed, when I called them that this is the second month that I'm paying for goods that are not in my possession they tell me that I need to patient! Can someone who is COMPETENT sort this mess up, or should I rather go and post a billboard where everyone can actually see my complaint