...
Blocking is a non-destructive action that prevents access to CrashPlan. A blocked user or device cannot sign in. This is useful to prevent further backing up of a device in the event that it has been stolen and you would like to retain previously backed-up data.
Deactivating is a destructive action that removes a device, user, organization, or plan from your Code42 CrashPlan environment. An active user can sign in again to a deactivated device, but a deactivated user cannot sign in.
To deactivate a device, find it in crashplanner, verify the guid, and click Deactivate under the Actions on the right side.
Deprovision Users
Deprovisioning a user removes the user’s account from the CrashPlan server and stops backup of all devices assigned to the user. It also stops billing for that user account.
...
The data in deprovisioned accounts will be removed from the cloud in 90 days. NOTE: If you need the data removed immediately, please include that in your request.
...