It sounds like you already filed suit in court against the insurer and lost.
Your only option is to file an appeal within the time limit to do so and convince the appeals court that the judge made a mistake. I would guess the chance of winning without a lawyer is zero.
You should know that this answer does not establish an attorney-client relationship. To do so would require a written agreement between us. You should be aware that there are time limits within which you must pursue any claim or suit.
There are two issues here. First, there is the insurance claim. What kind of insurance? Did you have to give them Power of Attorney as part of the application? If so, then the signature would be authorized. Assuming it was actually forged, you can contact the Department of Banking and Insurance and file a formal complaint. You may want to contact Federal agencies as well as this would be a violation of HIPPA. However, none of this will solve your coverage issue. Hopefully you had an attorney look at htat. If not, you should.