Upset and disappointed

Firstly if I could give no stars I would I am deeply upset as to telkoms terrible service. In April I signed up for a router contract which is 20gig day and 20 gig night. I signed up for this package telephonically, and when they asked which bank I want to be debited from I gave Nedbank the lady proceeds to tell me they will be sending me a debit mandate which I was completely fine with accepting anyways throughout the months telkom has not been making their debit so not wanting to be late on payments I did efts to their account which was an inconvenience however I did it not wanting my line to be suspended. Fast forward to 5 months later I get an email saying I owe 590 and here I am sitting puzzled knowing I made the necessary payments i then proceed to call telkom customer care and a lady tells me I been missing payments from my absa account so they are charging me the penalty fees. 1stly I do not own an absa account which I told the lady and she then proceeds to tell me they put the wrong account, 2ndly if they sent the debit mandate to the correct account why did the try debiting an account that isn't mine? And 3rdly why am I being charged a penalty fee for someone else's stupidity? When I ask this to the customer care agent she cut the call on me I am very upset and will not be paying money that I do not have if telkom cannot from their penalty fee for their stupidity they can discount their account I don't mind buying prepaid data I cannot pay funds I do not have for someone else's mistake! My payments are up to date I WILL NOT PAY PENALITY FEES FOR TELKOMS MESS