Sincerely, I guess that is better to create an responsive Facebook Group for the Mudbox Users, instead an irresponsive fan page.
One nice example of Official Facebook group for users ,with enormous activity due the efective response of their developers is the Marmoset Toolbag 3 Users group:
https://www.facebook.com/groups/ToolbagUserGroup/
Greetings:
Sergio Mengual
3D Artist-3D Generalist-3D Character Artist
https://www.artstation.com/artist/sergiomengual
https://www.facebook.com/Sergio3D2D/
https://www.youtube.com/user/sergiomengual