Locked out of extranet and the retrieval email is not available

an existing account providing accommodation in Adendorp, Karoo, South Africa is locked out of the Extranet and the existing email for retrieval to change the password is not available.  I am trying to assist the owner to manage his bookings, as at this stage his profile is available to the public, but he has no control over the bookings, receives no notifications of bookings etc.  Please can you assist in giving tips of how to unlock the Extranet to the business can function properly.  The previous assistant is unobtainable for the correct details to unlock the account.