Your employer denies that your injury is work related and therefore denies you medical treatment. Depending on why your claim is denied will depend on whether you may get benefits or not.

Your claim can be denied for many reasons including that 1) you were an independent contractor and not an employee, 2) you did not notify your employer of the injury until after you left your job (post termination defense), 3) there is insufficient medical evidence to support your claim, 4) the statute of limitations has run, 5) your injury did not happen at work, 5) you were traveling to work from your home or returning to your home from work (Going and Coming Rules), 6) intoxication, 7) self-inflicted injury, 8) horseplay, 9) off duty voluntary recreational activity, and more. For psychiatric injuries in particular they may also be denied if you worked less than 6 months or were a result of a good faith personnel action.