Dispute on a debit order

I cancelled my subscription in February, yet I am still being debited to date without any clear explanation. This is completely unacceptable and raises serious concerns about how customer cancellations are handled. To make matters worse, the contact centre is not helpful at all. Every time I try to get assistance, I am transferred from pillar to post, and no one seems able to take ownership of the issue. I have to re-explain my situation to every consultant, which is both time-consuming and frustrating. What is even more concerning is that they are unable to provide a reference number for calls, making it impossible to track progress or hold anyone accountable. All I am asking for is:

A clear explanation for the continued debits after cancellation Immediate stopping of all unauthorised debit orders