To adjust the number of users on your plan to right-size your account for your team size, you can either change the Boosted plan quantity via the Admin Dashboard > Account tab > Upgrade Now or Change Plan under the Boosted plan or make changes by following this link.

Once you enter and verify your email address, the Stripe management portal will open, and you can adjust your subscription.

Cancel your subscription by following this link, enter and verify your email address to open the Stripe management portal and adjust your subscription to 'Cancel Subscription.'

In the future, you can create a new organization account effectively, starting with a blank slate.