Terminating a Contract with ADT

It seems near impossible to cancel a contract for alarm and armed response services with ADT. After notifying them by email that I would like to terminate my contract in May 2023 and receiving a confirmation email and ticket number (Ticket: EE7EB58644D1E), it took almost 5 months to actually terminate the contract. Once the contract was closed, I received an SMS from their debt collectors (LGR Attorneys) that I still owe R581.74 for the notice month, which I agreed with, and did the payment on 20 November 2023. Now in January 2024 I again get an SMS threatening me with blacklisting if I do not pay the R581.74. This is not acceptable, please get you systems in order.