Re: verbal abuse from a teacher
Please, stop with the rationalizations. Leave. If you're part of a larger org contact them and tell them the certificate was lost and ask if they can issue a new one. Or just don't worry about it. I lost a handful of certificates when we moved to our current house over 10 years ago. They don't matter, they're just pieces of paper. If the organization is legit what matters is that they have records of your rank. If it's only this guy who has the record, who's to say he won't be a complete ass-hat and pretend you didn't exist after you left anyway?
Leave. If you earned the rank, you earned the rank. Heck, you're young. If you start over at a new place they might just start you at ikkyu or even recognize your rank based on your performance. Just be honest and let them know what was going on.
But please stop with the rationalizations. People have been quite clear and it seems to me to be quite unanimous. Leave. You've had advice from experienced psychologists as well as experienced law enforcement people. Leave.
Or you can insist on remaining a victim and stay giving all the reasons why you can't leave. While in the next breath you acknowledge that you should leave.
Stop for a second. Look in the mirror. Be honest with yourself and tell yourself what you would tell your best friend if she were in the same position as you.