Camden Living apartments oasi place no cooperation from corporate in houston tx las vegas, Nevada

I lived at Camden apartments at Oasis Place in Las Vegas, Nv. for over 3 years. I never missed a payment, never late paying my rent, and left the apartment in excellent condition. Priot to my moving, I went to the office and requested a final bill so that I could pay everything I owed Camden before I moved out. This was to be my final bill which included my last month rent, cleaning fee, and any other additional charges. I explained to the leasing agent that I would need to pay all charges then, due to the up coming expenses I will have in relocating to another state (Texas). She gave me an itemized final bill, which I paid in full accordingly.
 
A month later at my new address, I received another bill from Camden for $159.13. I called and spoke to the district manager, who was course and condescending, and threaten to turn the bill over to collections. Subsequent calls to corporate went the same way. I spoke with a Tammy Biggers and Martha Bellia, who consequently hung up on me today (9/24/2012). I have been unable to reach anyone else in corporate. I have tried to discuss and reason with the people at Camden on several occasions, to no avail. And after the condescending and disrespectful attitudes I've been subjected to, as well as the impossibility of reaching a higher authority at Camden, communication for resolution does not seem to be an option. I still have the FINAL BILL that I paid in full to Camden Oasis Place prior to moving out 6/25/2012. In essence, a final bill IS the FINAL bill.