System Error not corrected as promised for months

I have been told by the accounts department that an amount on my Edgars account was a system error (that affected many customers accounts due to the change over) and would be fixed by the next statement. (I have dates and references.) Every month since September my new statement is not fixed and I have to phone again. Today, when I phoned after seeing that it has not been corrected (again!), they have totally changed the story and are now saying I have to pay this amount! So did the others lie to me then???? What kind of games are they playing? It is ********* and called *****ing! This is completely unacceptable service from Edgars/RCS. I have asked to speak to a manager, but am still waiting....