Hi, I feel your pain.
First thing, try one more time to contact someone at the company. Get their name, and write down the response they gave you. If you get no further in your response, then try to remember who you talked to before and what they responded to you with.
Then, call your State department of Wage and Labor. It is very easy to report the problem. Give them details of what amount you were to gross, any and all money you did receive from the company etc. They will act on your behalf in the matter. Don't worry, it is also job security, no one can fire you with a wage and labor dispute. If they do, you call your local state Human Rights department and file another claim against them for unwrongfull release of duty.
Usually these things can be resolved very quickly. Wage and labor will respond in a short time. Employers do not like these people because it can cause them a whole lot of further investigation into their bookkeeping tactics and they don't want that.
The checks will come through wage and labor for all your back pay. The company is required to send it to them so they can record it, and ensure you were actually paid. They will then follow your case and ensure things are going smoothly till things are back to normal.
I know how this goes. Been there, done it. I now work on the other side. Companies do this to "bend you to their way" without realizing the stuff is gonna hit the fan, and it is illegal to hold pay without due cause and legal justification.
Let us know how it goes.