Extremely bad customer service

I've been with Debtbusters for a couple of months and in the beginning we came to an agreement of R5300 pm that I can hardly afford and for 2months that amount was debited from my account. Recently I received an email stating that my amount will now be R6918 which I won't be able to afford at all. I immediately rep**** to the email stating this. I phoned several times. I emailed Jean-Pierre who helped me in the beginning. I left numerous messages and still NO ONE can give me an answer or is willing to help me. If R6918 is deducted from my account on the 25th of this month I will go to my bank and reverse the amount and pay R5300 into Debtbusters account because that was the amount agreed on. I'm super disappointed because I had hope and trust in Debtbusters.