Deceived into doing an upgrade

I was called by an agent in October telling me that vodacom would like to give me a phone to say thank you for being a loyal client. I repeatedly asked the agent if it was not an upgrade and she said yes. I asked her again if I would still be able to do an upgrade in Feb and again she said yes. Fast forward, the phone arrived and I used it, it was a "free phone" after all. Come month end, I wanted to pay my premium as I never wait for the debit date, to my surprise my premium had changed. I called vodacom only to learn that an upgrade was done on my number. I logged a complain and I was told that vodacom would investigate and get back to me in 14 working days. I waited until I called and I was told that I would have to return the phone for the upgrade to be canceled. I let them know that I had used the phone and I was told that since I have used the phone I would not be able to cancel the contrac. I asked if I could pay for the phone so that I can cancel the upgrade since I was **** to, then I was transferred to another department where I was told that I would have to pay R22 000 for my contract to be canceled and the phone is only R3 500. Now I am stuck with a phone that I don't want all because they hire people who lie and trick client into the upgrades that they don't want. The phone is even a downgrade from the phone I am using now. I don't know if these people are trained to be ********* and basically force people into doing upgrades that they don't want. I can't do an upgrade now like I had planned all thanks to their agents. What about my consumer rights. I'm highly disappointed