Refusing to cancell my diploma course

On the 24 October 2019, I went to one of their branch in Pretoria to cancel my diploma course,I was told to write a letter stating why I want to cancel and I did when I return to submit it they told me I am not in their system, so I must call their cancellation department and those they never answer their phones then I went to student portal and sent a complain then Eunice Sababo rep**** she told me to send her a email about why I want to cancel I did that on the 8th of november 2019 even now she never rep**** i call her everyday but she doesnt answer, this is poor service delivery all they know is to call and damand money, I am so passed I regret why I choose this institution