Hi Jennifer,

All the products of Reviversoft are easy to use and helps you to keep your PC up to date and secure.
For example, PC Reviver is a multi-purpose utility that will diagnose errors on your PC, safely repair them, and provide other maintenance and optimization recommendations. PC Reviver is the trusted and recommended way to restore optimum performance and stability to your PC.

If you still don't want to use the services, I think you don't need to cancel your subscription as your license will remain active until its expiry date and it will not get auto renewed after that.

But if are still want to get it canceled immediately, you can contact the support team at the below link:

Support

A representative will help you out in a timely manner.

Regards,
Lokesh