Telkom is and *********, money *****ing company

Telkom is the most ********** company that Ive ever dealt with. They were deducting funds from my account, i had no idea where it came from. They told me that i was on a postpay account (which is not what i requested when i signed the contract). It took me a year to get a copy of my contract because the store where i opened the account as well as head office kept on telling me that they don't have it on record. This in the first place is ******* and the service Ive been receiving is ridiculous. When i told them Im going to cancel the debit order until they are able to provide me with a copy of my contract the store manger threatened me with legal action if i do so. During this process i went into a branch and requested that they change the account from postpay to prepay (this is 6 months ago). My account with Telkom has now ended and they are still deducting money from my account due to them never changing my details to prepaid. I cannot get hold of an agent over the phone they only bring up a bunch of self service options because they are obviously very aware of the ****ty ethics that this company is run on and refuse to deal with their customers. Can someone please tell me how to get hold of someone within Telkom that actually knows how to do their job and assist me?