Bad service and refund requested

I have a payment arrangement with GLA and my debit order date should be earlier than what was added to the system. I received a email right after my supposed to be debit my order date about missing payments. I rep**** back and said I will make a payment and asked what happened to my debit orders order date..no respond. At the end of the month the debit order went off!!!! I emailed both the consultant that emailed me and the credit officer requesting a refund and till today no respond (used to this when I need questions answered). I also wanted to know why does outstanding balance not drop!?!! Isn't it when you have an arrangement payment plan, the account does not accumulate more interest? If I am going to pay this thing for the rest of my life without the balance dropping, what the point in forcing myself to give more while I am struggling on a monthly basis.