The last time I called the garage door company they charged me $200 so I don't want to mess with them. My door won't stay closed. It will go all the way down sometimes, sometimes it will stop a couple of inches above the floor, and then go back up. There's nothing between the sensors, the sensors are clean, it just won't close. If I stop it on it's way back up and then hold the button, it will close and stay closed. Does anybody have any ideas about how to fix this?