Need advice. Former car dealership employee.

Got fired on 7/19 for telling the owner of my company that I was contacting the DOL over my wages constantly being incorrect and nobody fixing it.

I had a contract in place as well stating that if I didn't turn over 25 hours in a 40 hour week, I'd get a $800/week base pay. I'm a mechanic on flat rate (comission) for reference.

They haven't paid out my weekly guarantee correctly ever either.

2 days after being fired the service manager texted me telling me the owner wanted to discuss what was owed to me.

I get there, he tries to tell me he only owes me for 15 hours when I had over 30 before I got fired. Then when I asked him why did it have to get to this point if I'm not in the wrong, he said I threatened him with the DOL. I told him I didn't threaten anything and he couldn't do that, that's considered retaliation and his response was "I've been in business almost 40 years, you're the first one to have an issue, if the state gets involved who do you think they'll belive?" And I told him I didn't care if he was in business for 40 years or if he's done it to 1 or 100 all it takes is one time and walked out. I got a final check at the 15 hours, which was incorrect. What are my options for indiana?