Telkom has not cancelled my service after numerous requests

I have contacted Telkom on numerous occasions since March 2018 to cancel my adsl subscription, only to be told that I must wait for an agent to call and confirm my cancellation. They are still debiting my account every month for a service I no longer want or use. I want my service cancelled ASAP, my money to be refunded and my deposit to be refunded. This is ridiculous!!!