If you need to add a contact to an existing listing, simply add the contact by doing the following:
Open the listing by going to the list of properties in your database, or
Open the listing by entering it's reference number on the dashboard,
The mandate information will now open on your screen,
Click on the "contact" item on the right hand side of the mandate summary,
Click on "Add new contact" and fill in the required fields making sure to link the contact type e.g. Seller/Tenant etc.
Save the changes