Questionable practices!

I cancelled my son’s enrolment after less than 2 weeks of schooling and had a 3 month fee termination to pay. Both parties (UCT & myself) entered into a 9 month payment arrangement which started in Feb 2025. Yesterday I received an email stating that if the full outstanding amount is not paid I will be handed over for debt collection. I have stuck to the payment arrangement but I am being told that my billing cycle ended 1 April 2025. I am unclear as to why a payment arrangement was agreed to if I was to be struck with the above. Questionable business practices and ethics. Truly disappointed. At this point I would rather source the funds for the balance and settle UCT and cut all ties. Truly astonishing!!!