I got myself into a state where App Store says that I have numbers "installed" but in fact I don't have it installed. I tried the recommended option/click and shift/click over the installed button and it didn't work. Can you give me a tip?
Try resetting the Mac App Store.
Enable the debug menu and restart the Mac App Store.
defaults write com.apple.appstore ShowDebugMenu -bool true
Choose the Reset Application option.