Contractor says I owe for materials

I had to fire my contracting company I hired to renovate 2 bathrooms, new floors etc because everything they did had to be redone. They got to the flooring part of the project. Bathrooms not finished, have been without a toilet in main bath for 2 months. They Poured leveling cement, they then fired the guy who did that part who worked for them saying he did a bad job. Then proceeded to stall saying the leveling was going to cost too much now even though I paid set pricing. They stalled 4 weeks, then the flooring company they hired to finally finish the job said they weren't willing to do the work because of levelling mistake before them that they could not warrantee their work. So I finally had to fire the contracting company overseeing the project. Now they say I owe them for the flooring they provided months earlier but never installed. I have paid progress payments throughout the project they never finished anything 4 months later. I am pretty sure in those progress payments the flooring must have been paid for because I've had it in my hallway for 2 months. I have been dragged through the mud by them, nothing done right, insulted when I pointed out my tub was damaged by the glass installers, and not leveled properly. Can I just tell the to prove I haven't paid for the floor yet, cuz I dont have any invoices to prove or disprove this. What do I do? I am paying another company now to install my floors.