I have never had a closed location with them in the decade or so I have been doing shops for them and I see nothing in their FAQ about closed shops. If I found a location closed which according to the client website was open, I would 1) make absolutely sure that I was at the correct address and 2) take photos that would substantiate my claim that the location was closed. If I had a smartphone I would probably call my Account Assistant while I was at the location to ask how they wanted it handled, otherwise when I got home I would email my Account Assistant to see how they wanted it handled.