Invalid Billing Mancosa

Hi I have been incorrectly billed by Mancosa for my studies. Signed up as a distance learner and as the year went on my fees were changed from distance learner to Tutorial attending. Reason being they say I attended a class yet the only classes I attended were the ones I was emailed about. Secondly all the people I attend workshops with that are distance learners have been correctly billed. I have sent alot of emails to which the finance manager said he doesn't care he billed me correctly. Yet my proforma invoice and amount deducted per month were structured as per distance learner.