Overcharged on my Telkom Account

I have been overcharged for almost two months after I have cancelled a contract. I tried calling customer care without any success. When I call they transfer me to different departments and they hang up phone after that. My contract expired on the 22 August, but there is new subscription called "Account subscription & once off charges" that goes off every month. Please rectify this and refund my money as I cannot get hold of you. Account ***, A***