Mislead advertising

I got a call from on air TV sales agent, what we spoke about on the phone is not what I'm receiving or experiencing with their decoder. I was told that I would be paying R139 for the services but to my surprise when I call multichoice I am being told about an extra R95 activation fee. Called on air TV to cancel and I'm told I can't cancel. Please come and take your decoder because this is ******* till today I've got no contract from them.