Disgraceful service from Vodacom

In mid march a sales operator called me and offered me a vodacom router, I am not one for buying things over the phone, but the agent asured me that the device was FREE and bacuase I was a vodacom client for so many years they are giving me this as a reward. I asked him about 10 times if the item was indeed free and I will not be paying anything extra because I cant afford anything extra and he assured me me that It was free. To my understanding what I agreed for was a free router, I was unaware of any additional costs otherwise I would have not accepted the offer.. After a few days of receiving the item, they request money from me and at the end of April they took the amount from my account. I tried calling vodacom so many different times and I am not getting anywhere with them. They refuse to reverse this transaction and say that I agreed to the contract. If I did agree I was not aware on what I was agreeing for and I have not signed any papers stating that I wanted this contract. The item is still sealed in the box and unused. Every time I phone them they refer me to another number to call, when I call that number they give me another number, nobody seems to know what's going on. As a client of Vodacom for over ten years, I think it is very disgraceful on their part as to how they treat their loyal customers. I am so dissatisfied with Vodacom and their pathetic service. I will no longer be using them as a service provider.