Payflex credit

I have used payflex for a long time now and have never skipped a payment until recently when I missed a R186 payment due to issue on my account and details. I paid the late fee I paid almost R400 for a R186 installment a d now they have taken my credit and I have been emailing them and I just get a robot replying me. If you pay the penalty and they see you have a excellent track record with them why do they take your credit away?? I had a refund d from takealot and wasn't processed on my payflex. How do you get your credit back and your refund to appear???