I cancelled my application within 30 days of the required cancellation period but intec refused to cancel now they have handed over my account and im listed as a bad payer

I have nothing but bad treatment from Intec college consultants, I wanted to upgrade my matric marks with Intec collage, I did my application and I registered with them, then I was supposed to go to the department of education to register for an exam center when I got there they told me registration have already been closed the previous year n I will have to wait for another year to register again, so then I decided to cancel my application because I was not going to write exams in any case, my problem was how can you allow me to register whereas the institution knew registration for the exam center where closed they miss leaded me to their gain they took my registration amount and wanted me to pay more on top of what they took out of me they disputed my cancellation saying I should pay a certain amount in order to cancel and I felt that was unfair on me because I cancelled within the 30 day period required for cancellation, now this dated years back I call Intec requesting all the conversational emails between me and them during the time of cancellation they refuse to send it to me and the consultant was very rude to me didn't want to listen to what I had to say. I have heard so much good about how you handled other peoples case I hope you will be able to handle mine accordingly because this company created a bad name for me.