If you've been deleted from your organization's system by someone in that organization, you would need to contact that person to find out further details. The email notification you receive from the system
informing you of this deletion will contain the person's name who deleted you from the system which you can contact for further details and/or an explanation. If you can't find or no longer have a copy of that email, you would still need to contact your local organization for further details. Unfortunately, the technical support staff cannot and will not be able to reinstate your account for any reason. You would need to register for a new account or have your organization grant you access in order to regain access to the organization's system.