Where can I purchase the Roseburg redi- shelves?

I've been continuously looking for the Roseburg redi-shelves, but cannot find them. My contractor put the shelves in my pantry, but didn't add an additional section as I asked. I need to find one order three shelves, but cannot find any place that sells them. I'm hoping someone can help me with this issue.

roseburg redishelf unfinished particleboard shelving shelving