Tracker the worst ever

I cancelled my contract with Tracker on the 1 December 2022, only to receive my cancellation letter a year later dated 31 December 2023. All outstanding money was paid. Then came Dec 2023 and a debit order was put through by Tracker on my bank account. Without debi-check. This was return by my bank marked unpaid with bank fees. The same happened for Jan and Feb 2024. One year later and I still owed them money. Really! According to may bank they are unable to stop the debit order and I have to stop it with Tracker. But according to them I still owe them money. Really! Are they so desperate? I will NEVER make use of their services again.