Your dad isn't by chance a politician or car salesman is he?
You know life sucks when you go to ask your parents for money and they end up asking you for some first.
I said this before in a previous answer, I'll say it again; ever notice how, if you invent or discover or are given something kind of cool, there will always be somebody who wants to take control over it?
Ok, so where did the money come from? Was it given to you as an allowance, and now he wants it back? In such case, maybe it started out as his money, but was given to you. If you have a job and earned the money, why is he asking for it? Are you over 18 and still living with him? If so, he could technically charge you for room and board. If you're under 18, I don't know that it's right for them to demand money from you.