Telkom messing with my credit record

I’ve been with telkom for years, no hassle. Recently I keep on receiving harassing messages to pay m account, messages sent to my friends too saying I should pay an amount that was already debited on my account. When I call them I can’t get hold of a consultant and if I do get one they can’t help me. I received a message saying I’m listed for an account I’m up to date on. I’m very disappointed in Telkom’s service and it’s so frustrating for no one can assist. They even sent a debit mandate to my bank account of amounts I don’t know of.