CANCEL MY CONTRACT, PLEASE!

I cancelled my contract as I don't want to upgrade. I saw this month they tried to bill me again. I need my contract to be cancelled effective immediately!!!! Please stop trying to get more money out of me for something I no longer want by not cancelling my contract!

Also when going to the Cape Gate store to try and get help as the call center is not helping me successfully I got helped by a very rude Vodacom employee who raised her voice at me, shrugged her shoulders and told me it is not her problem.