Not cancelling contract and *****ing my money

I was "*******" over the phone by a telesales person into a new contract after making me believe it is only an upgrade on my data contract. Realizing the mistake, I phoned the following day to cancel the contract immediately. The wifi router was delivered to me and I requested for it to be collected again. It was collected on the 3rd December 2018. I was told that I can only cancel the contract once the warehouse received the device. I phoned a week later, it was confirmed that the device was there and the lady told me that she has logged a request for the cancellation, she also said I will receive a text message to confirm the cancellation. I have not received anything and money was deducted from my account. I went to Vodacom head office in Cape Town yesterday - 8th January 2019 to ask to speak someone in person. Faiz was too busy to come down from his office, and only told me over the phone at the reception desk that a request was logged for my credit. I told him I still have not received a notification that this contract has been cancelled either. He gave me a reference number and told me to phone 082 135. I have been phoning non stop since last year to try and sort out this problem. I received another invoice this morning 9th January 2019 and this new contract has still not been cancelled which mean Vodacom will be *****ing more money from me at the end of the month.