If I tell a kid not to ring my doorbell before 7, they better not ring my doorbell before 7. The kid's not made of glass, I have a right to sleep, and it's MY doorbell. You people sound like he took a golf club to her.
He didn't make her cry- her parents made her cry by not teaching her to pay attention when an adult talks. It wasn't fifteen minutes early, it was TWO HOURS, and he'd told her many times. Seven years old and can't respect other people's property or handle extremely simple instructions? I could handle "don't do X before X" when I was three or four.
However, there are better solutions. Did you tell the kid you're sleeping during that time? Did you ever go talk to her parents? Why don't you tell your kid to go over to their place instead?