Very Poor Customer Service

I am in the process of cancelling my account with ADT as we have opted to go with a new service provider due to the escalating costs of ADT's services that we simply can no longer afford (plus their poor visibility in our area). I informed ADT of this request on 08 September 2023 and, despite their valiant attempts to retain me as a client, my request was only processed on 18 September 2023. I was also informed that it will only be effective on 30 October 2023 since a calendar month notice is required; and that a further debit order will be deducted to cover this notice month. Despite my pleas for them not to deduct a full month (seeing that I did notify them on 08/09); and I have told them that I am willing to pay a pro-rated amount for the 1 to 7 October 2023 period; ADT insists that it is part of my agreement and that I need to give a full calendar months' notice - and pay accordingly. I think this is poor customer service as it does not take the client into consideration at all; and they are not even willing to negotiate - It feels like I am being punished for cancelling my account.