When trying to remove a user from the Team to prevent from billing, there are two options that can be performed:
Banning a User
When you want to permanently remove a user from the Team you can ban the user. This is a permanent action and users once banned from a Team cannot be unbanned in future. Follow the Steps mentioned in the link below to ban a user from your Team and block their access to your team's information:
Disabling a User
You can remove a user from the Team by disabling the user. Once a user is disabled from the Team, he/she will loose access to ALL Team Storms. The user can be enabled back to the Team anytime. Follow the Steps mentioned in the link below to disable a user from your Team.