Never Received Final Bill

I broke my lease about 6 months ago and have still yet to receive a final bill from my apartment complex here in northern Virginia. The final bill should include an early termination fee of one month's rent making it a decent sized bill. I've tried calling the complex twice now trying to get a final bill and providing my updated address both times, but still have received nothing.

While I'm perfectly content not paying, I'm worried that may cause legal issues down the line. Therefore I was hoping to get some advice on the best way to get written proof that I tried to obtain a final bill or some other way to cover myself legally. Should I write them a letter and save a copy or is there some better way to go about things? Any help and/or suggestions would be much appreciated.

Yes, a letter confirming what has happened if often a good idea. And it is often a good way to document your version.