Black screen after champion selection

You guys constantly ignore this specific issue for mac computers. Please fix. I've spent over $100 on skins/content in the game and i feel like I'm being robbed for having not been able to play for almost a month due to black screen appearing after champion selection and apparently "freezing". Nothing i do works as in restarting the computer, deleting certain files, ect. I've posted this before and no reply and so have others.