How do you calm your parents when they blow up at something you have not done?

I gave them some paperwork to them because I was not legitimately able to fill it out or turn it in. Now, they are saying I didn't. They are threatening me to the point of disowning me. I know for a fact I put it into their possession immediately, no middle man, and no messes it could have been lost int. I remember the conversation to a tee. But, due to the lifestyle I choose to live (gothic), I am a "Devil spawn" and am never, ever truthful, when in reality, I have never lied to them or done anything like this.