Unwanted Services Activated

A sales agent who goes by the name of Valene phoned me on the 17th February 2016 to offer me a package deal. She made it sound like my current package is being upgraded with no additional charges, which seems strange, because why would Vodacom upgrade a package for free. I repeatedly asked her if there will be any additional charges and she said no. I then received a confirmation email from her that whatever is being upgraded is in progress. I phoned customer care because I was unsure and after being sent from pillar to post realized that this is another package added to my account, where I then immediately, repeatedly requested for this to be cancelled. After numerous emails I received a confirmation email from Ntsika Xesi on the 19th February 2016 with a reference number to confirm that this will be sorted out. I received a statement from Vodacom yesterday stating that I now owe R786.50. I WILL NOT PAY FOR THIS AS I HAVE CANCELLED WHATEVER THIS IS 3 WEEKS AGO!!! If my account gets debited with this amount, I will cancel my contract and move to another service provider. And I will sue Vodacom!!!