You can cancel your plan online by chatting with an agent 1-888-795-3460
Here's how to do it:
Go to the Best Buy website Click on Services in the header Select Chat with a Geek Squad Agent from the drop-down menu Enter your email address and click Chat Now when the Remote Support page loads Follow the instructions and cancel your plan

https://sites.google.com/view/contact-geek-squad-supporrt/home