Webwatcher — internet monitoring app

I purchased the spy app from webwatcher in approximately June 2019, and paid with my Visa debit card.
I complained to the company that I could not get the product to work and told them to cancel my subscription with immediate effect.
This week I noticed webwatcher had debited $39 from account without my permission.
I have never used this product and request immediate refund of the amount debited back into my account.