DAMELIN BOKSBURG sort your departments out and get off my case

in July i went to Damelin Boksburg to cancel my N4 course with them for personal reasons, they told me to go in i went in spoke to the sales person that signed me up and the sales manager, they told me to write a email and send it to them they will then sort it out, i did the N3 course earlier the year so the N4 i cancelled even before we wrote the N3 final exams, now i keep being told i owe them money spoke to numerous people in their accounts department and was told to send a email AGAIN i did this and still i am being harassed, i forfeited my deposit due to cancelling!