From their FAQs:
Thank you for trying Score Watch Free Trial, we hope you found our product informative, helpful and of value. To cancel or convert your Free Trial, please contact myFICO Customer Care:
Click here to send an email.
We will respond to your inquiry within two business days.
Mon-Fri 6am to 6pm Pacific Time
Sat 7am to 4pm Pacific Time
Since I had a few days to spare before the cancellation deadline and I didn’t want to deal with talking to a live CSR on the phone, I clicked the link to send them an e-mail. When you do that, you’re taken to a form where you can click a radio button for “Cancellation, ” and another one for the product you are canceling (the “Score Watch Free Trial“).
You’ll then be taken to a form where they ask you to enter some personally-identifying information to complete the request. Note that they did ask for my Order #, though it wasn’t required. I went ahead and dug up my confirmation e-mail just to be safe, but you should be fine without it.
That’s it. I received confirmation that they had cancelled my trial the next morning. Very, very easy.