Refused Chinese Visa :(

Hi everyone, I have just been refused an 'L', no reason given. I have almost filled my US passport (on it's last four pages!) with only Chinese visas! I have two questions, firstly how long do I have to wait before re-applying? Also I am a dual national, can I apply using my 'other' passport which is brand new? My fiancée lives in China, all that I own is there! I need to get back ASAP! Any advice would be a bonus in my current situation! Thank you.