Cheated customer by multichoice

My name is Andrew Matthews i'am not happy with the response i got from multichoice. I have been paying for their services with no hustle. Until i asked to upgrate my contract i was i assisted by lady named Ofentse Molemane instead of upgrading me she made a new contract a sale on her side. Which only benefited her. And got be into a debt with multichoice. I'm being told i need to pay 0ver 400 which is not fair. I only requested an upgrade.i need assistance as I feel cheated and used by this company. I have went and called but no one is helping me.