Problem Unable to update Play Store

I recently purchased a Kukele S912 android tv box. Everything works well except the Play Store. I must clear the cache EVERY time I use the app or it will not open. I tried to update the Play Store to a newer version but the apk says "Unable to Install Apllication". I tried putting the apk in the android root app folder and restarting. It actually updated but the new playstore was unusable. It would load but I couldnt install or update anything no matter what I did. Had to put an apk of the old version back into the root folder and reinstall the original version.....with the original issue.

So... does anyone have any advice on either fixing the current version of the app or installing a new version? I can't seem to do either.

Thanks.