How do you stop payments

If a client requests their subscription to a product be stopped, how do I do that? I have gone in an clicked no to taking the payment and it still does. This is happening over and over. I have stopped access to the product. I have put all the tags saying to stop access and still the people are being charged.
This has gone on for months now, and I’m baffled as to how to make this system work for me.
My email is
Thank you for any assistance

@Leonie_Blackwell, are you following the instructions in this article to stop a subscription? Cancel your customer's subscription | Max Classic