Livid client

My experience with Pretor has one of the worse I have ever experienced. The account clerk is very disrespectful speaks to people like they're stupid,like she is doing me a favor.i had an agreement to pay an outstanding amount of R3700 plus my monthly levy fee and to my surprise today I receive my latest statement saying I owe R11900. When I enquire she speaks to me like I an idiot and refers me to their lawyers,they then tell me the same lady gave them an instruction to go ahead with legal proceedings. I have been paying as per my agreement and to now get this bills just makes me very angry as that means I have to now pay more for another 9 months. Do they even understand what an extra R1000 does to my life?