Once a group (Team/Class/Camp) has been created it cannot be deleted. We don't want you to lose any potential history associated with that team. It can, however, be inactivated so that it is concealed in DASH. This will allow you to resurrect the team through a Season or Team export, should the need arise.
You cannot deactivate a group that has payments applied to it; you must either reverse all payments or transfer participants to another group.
You can Searching for Inactive Groups from the Team/Class/Camp Search page, in case you need to refer to them for payment history or verifying information.