Can not install Kodi

Hi,
I have totally stuffed up my Kodi!!! I was trying to update it as I had an old version 14 something, however it told me to uninstall Kodi, which I did. And now we cannot download/install any Kodi from any website. I have tried everything, it downloads but I get errors saying ‘can not open file’ or I try search for it under local disc and it says ‘no apk found’

I have he M6 android box which was XBMC/Kodi
Please please help me get Kodi back!