my ex employer is withholding my last paycheck, is that illegal?

I worked for a company regarding ambulance transports. I quit and they refuse to give me my last paycheck. They told me that i need to come in and fix paperwork that i did over a month ago. I went in and did what i could on some of the runs but i did not fix a few because they were asking me to fill out the whole patient summary form. That includes vitals of the patient, insurance information and the patients demographics. I refused to do it because if I fill it out to the best of my ability then it wont be acurate information. If i falsify patient information then i could get my license taken away because that is illegal.  I also told them if I'm there fr an hour doing paperwork then they need to compensate me for being there because they're taking my time to do work that they feel is unfinished. How do i get my check if the refuse to give it to me?