I'm sorry to inform you that you are much too late to appeal your unemployment denial. The normal appeal period is 30 days. You can appeal from 30 days after the determination until a year after if you have "good cause." Now, even with good cause, you are too late.
Your rights may (or may not) have been violated under the Family Medical Leave Act (FMLA). The deadline to file suit under this law is 3 years for a "willful violation" and 2 years for violations that are not willful. You may (or may not) also still have rights under the Michigan Persons With Disabilities Civil Rights Act. Consult with an attorney promptly to understand and maintain any rights you may have.
...Do you think the general manager's references are knowingly untruthful? Usually employment references have at least qualified immunity from defamation suits but if the general manager told lies about you and he knew he was telling lies about you, perhaps there is a possible claim.