The majority of times when a user receives a "REF Number: ******** is already selected, kindly review the following list." (which is the message you may have received if you tried to manually add a listing by clicking Add Property from the menu) is because there is a listing with the same Ref Number from an automated feed adding the listing to your account or even possibly from another agent or from someone's MLS that is in ProxioPro.
Proxio receives an automated feed of listings from many partners that will add listings you are the primary listing agent for to your ProxioPro account.
Listings from automated feed of listings are automatically added to those agents who are members of the ProxioPro partner without you having to manually add the listing by clicking Add Property from the left menu and enter the listing information.
To view your listings, navigate using the left menu to MY PROPERTIES > Property List. Click on the REF No. of the listing you would like to view to see the 'View Details' page for. Note: Also after clicking Property List from the left menu, next to each of your listings, you can click the number under the camera icon to display all the images for that particular listing.