Unauthorized ADT Debit order

On the 26th of January 2020, I called Fidelity informing them I want to cancel my contract due to the pathetic services received. Thus, for all the emergency alarm activations that occurred in my house, ADT security personnel arrived after 30 minutes to 1 hour. I raised the issue with their Pretoria regional manager and prompt service was promised in the future. However, no prompt response was forthcoming. The other minor thing is that my unit was no longer on rental but my monthly premium was higher than on my other house unit which is still on rental. That was very strange to me but I continue paying. ADT consultant called to convince me to stay but I stood my ground. He then informed me that the last debit order will end on Feb 2020. In order to protect, I requested and e-mail address to send the cancellation request through which I did on the 2 Feb 2020. Now, greedy ADT went and debited my account on the 26th March 2020 though I have given them 30 days' notice. The worst part, I did not receive any services or notification from ADT during March 2020 such as SMS indicating that the unit is disconnected from the power supply which I did at the start of March 2020.