I cannot access a homescreen or settings on Galaxy Core after android 5.1 update

[AC Question]

My Samsung Galaxy Core kept asking to update to Lollipop 5.1. Now I cannot use my phone. I cannot access anything. The update has not gone past the End User Agreement, when I tick everything and press next it does nothing, it will send me back to restart at times.. I have restarted and also removed the battery and when turning phone on it opens to the End User Agreement Screen. I cannot access settings or anything. It will however let me use the google launcher, but I'm not sure exactly how this screen comes up. It is no longer a phone. I have access to nothing. Please help!