Billed for 5 subjects and but only registerd for 2

In Oct I September I registered to write 2 subjects but the wrong 2 were captured by the exam department, I immediately asked them to correct which they did but I was still billed for those subjects. My account was suppose to be R900 but is now R2250 and it seems as if I am a bad payer. I am sent statements that I am 3 months in arrears. Not only am I registered as a bad payer I can not see my results which I have paid for.This is so unfair