Cell C robbing me from my paid up letter

On the 1st of May i walked into a Cell c store to cancel my cellphone contract, i was given a settlement quote and was adviced to do an Easy payment at a Game store because it was a holiday, i went back to the store and the consultant asked me to write a letter that she scanned and made a call, I was given a reference number and a TPHD consultants name that was supposed to call me back within 24 hours. I've since been taken from pillar to post as every time I call customer service my call gets hung up and my contract is still not canceled.

And most probably Cell C is going to request me to pay extra for something they did not do on their side.

Please assist.