Can't reinstall league

So my League client randomly crashed, so then i tried to reopen it and I couldn't. After that I decided I'll just uninstall and reinstall, which may have been a bad decision. Now I can't even reinstall the game, and when I went to the Riot support center I couldn't even log on there to send a report. Someone please help, I'm on a Mac btw.

Whenever I go to install it it just shows a white square then just stops.