Poor Account Management

In August / September 2015, I received a phone call from my father in law that Teljoy was trying to contact me with an account enquiry. A lady by the name of Portia informed me that my account was in arrears, which shouldn't be the case as there has been a debit order in place since I opened my account in 2009. I confirmed with Portia telephonically that there should be a debit order in place, PLEASE GO AHEAD AND FIX IT AND DEBIT WHAT NEEDS TO BE DEBITED. I checked with my bank to see that all was in order and saw that there were no problems to be reported. Today I get an SMS from Teljoy notifying me that my account is still in arrears and that I need to make a payment today. I phoned Teljoy again and spoke to Portia to ask why it wasn't rectified and why I am still in arrears and received no valid answer. I requested a manager and spoke to Verona, who also couldnt answer me but apologised. I was then told that I need to pay more than the contracted amount becuase its not on debit order plus the amount I am in arrears due to Teljoy's negligence!! How dare you penalise a customer for an error clearly made on your side of the wall. I would like a senior manager to contact me!