If you want to stop using Kaspersky Endpoint Security Cloud and Kaspersky Security for Microsoft Office 365, you can delete your account from Kaspersky Business Hub.
When deleting an account, all data associated with that account is lost.
After you delete your account, you can no longer gain access to your workspaces in Kaspersky Endpoint Security Cloud, Kaspersky Security for Microsoft Office 365, and Kaspersky Security Center Cloud Console. If you were the only administrator in a workspace, the workspace will be duly deleted. Additionally, you lose access to your My Kaspersky account.
To delete an account in Kaspersky Business Hub:
The User account settings window opens.
The Delete user account section displays information about the consequences of account deletion and, below that information, the Delete button.
The Enter your user account password window opens.
Your account is deleted.