Yep! You can cancel at any time, but keep in mind that all new BURST membership plans come with a 1-year minimum commitment. If you decide to terminate your plan before the first 12 months of membership have elapsed, you'll pay a one-time termination fee equal to the balance owed on that first year. This amount is calculated to cover the cost of the starter kit(s) provided when you became a member.
Here are the BURST Terms of use for the membership with all of the technical bits: https://www.burstoralcare.com/terms-of-use