Line added without approval and cannot cancel it

In May I performed an upgrade on my existing Cell C contract, however, instead of doing an upgrade, a new line was added to my account, which I did not approve. I have been trying to cancel this line for over 3 weeks now with no success. I have requested the cancellation and have been told twice that a courier will collect the device however this has not happened. I am being billed for a service I did not request and the call recordings that you have will confirm this, please can someone assist in canceling the line as today I have spoken to 3 different people just to get cutoff.