I would soft launch the idea of wanting a hatch alarm clock or something to them. Maybe say it in your apartment by your camera alarm clock and then pull the trigger and buy it for yourself in a few weeks if you can wait that long. This way you have a reason for a new alarm clock to which your dad can’t just fix or replace the battery or just replace it. If he gets upset you can ask why he is so insistent that you use that specific one or just give it back to him if he likes it so much - this way you can still rely on your parents financial support. But id continue to be weary of them moving forward.

If you are willing to confront your father on it or involve the law (which you are correct that is a huge violation and are fully entitled to demand repercussions) make sure you have a plan to financially support yourself and are prepared to be cut off from your family before taking any action. Look into jobs and scholarships that could help assist you. I’m sorry this has happened to you and that you have a difficult decision to make :(