It is unlawful for a binary broker to allow US investors unless the broker is willing to submit to regulatory oversight by the CFTC. This one is not, so the very fact that it let you open an account with them means that they are not on the up and up. Are you saying they won't let you withdraw your profits?
optionking.com's website was just revised last month and has no screenshot history. It will expire in 3 months if not re-registered. It's IP address traces to the UK, which does not regulate binary option brokers. Some UK binary brokers have registered with the UK's Financial Conduct Authority anyway, to show that they are legitimate, but this one has not. Nor is there any record of any firm called Option King or Optionking.com in the UK's corporate business register.
The site itself provides no hint of where this company really is, beyond a toll-free numbeer and a dialogue box on their website.
We hear daily horror stories, just like yours, from customers who have invested with unregulated binary brokers, all of whom are operating illegally and who make their own rules. If you can find them, then you can sue them for your money, but finding them looks like it will be a job for law enforcement.