Vodacom continues to bill yet device returned

For the 1st time I decided to take a contract over the phone through elite mobile who did deals on behalf of vodacom. I took the 7 inch tablet with 500mb of data for R79 a month. The consultant was as sweet as honey and even went to the extent of adding features to the device which were not there when i received the unit...she said it took an external usb which was a lie so i decided to cancel the contract i did not even activate the sim so NO DATA was used. RAM couriers collected the devkce from.me ref Y***. I contacted vodacom 3 days later and was told the contract was cancelled. So i proceeded to take a contract through game gateway and was told i only have 1 contract with vodacom. To my dismay i have now received a bill from vodacom for R79 which was deducted from my account on the 31-12-15. When i contacted customer care i was told its too late to stop the debit order as it is automated what nonsense! Am i supposed to pay for a device and data that i do not have? I was then told that i will receive a ref number for my query lodged as apparently the consultant sent an email to accounts to credit me and cancel my debit order. That ref number was nvr sent to me! DISGUSTING!