I'm feeling your pain because Daddy was just AWFUL!!
He used to pee AND poop in his cage every night and a lot of times during the day too. Sometimes I'd be gone 25minutes to go and take or collect the kids from school and he would have peed or done both whilst I'd been gone. That was after making sure he'd gone outside before I left. Of course he would stand in it or lie in it and it's very overwhelming when you have a puppy covered in .... the bottom of the cage and all his blankets are covered in ... and then because he's stood in it then jumped up because he's so excited we're home again, the sides of the cage are also covered in .
For us the only thing that eventually helped was time ............. he just gradually grew out of it! Took between three and four months!
Sorry not much help!