How to cancel a subscription for good?

I had an MLS Season subscription last year with automatic renewal option.
That expired last February. So I assumed it was for good, as I wanted. But
suddenly I’ve noticed today, that it was renewed and I was charged for it
again. I have been trying to unsubscribe from it, but I could not find a
way to do it. In the Settings I can easily do Renewal, but not
cancellation, even after googling for the way to do it. Has anybody here
managed to do it, and how?