Can a former employer hold your last 2 checks and change the rate of pay?

I worked for a gas station for a month. I had a "no call no show" (Obviously i didn't care for the job) Although it's grounds for immediate termination they took it as "willful termination" i.e. I quit. What i want to know is if they can change the rate of pay from $8.00 an hour back to the state minimum on the money/hours they haven't yet paid me for? I live in Ohio and at the very least i would like to know who i can contact either to find out if it's legal or to make a complaint against the company.