Falsley Accused of Falsifying Expense Report

I was terminated 9/23/14. My boss said I claimed mileage I didn't drive because the rep onsite didn't see me (not unusual). He then stated there were a lot of reasons but wouldn't tell me. I called HR and was told there was no specific reason other than moving in a new direction. My boss called back and when asked told me I would find out when I applied for unemployment. I was made to drive over 500 miles to turn in my equipment rather than letting drive 1.5 hours to turn it in. I was told I would be reimbursed for mileage. I received an email from my boss today telling me I would only have been entitled to half the mileage, (they weren't paying my mileage home) and that I had falsified another report and I owed them money. I was never asked about this report. I have never knowingly sissified anything. It is possible that the last report I submitted I might have gotten the days mixed up, but not the locations or where I went. There is no proof. Is there anything I can do?