This is not a case in which the bona fide marriage is an issue. I just do not understand why USCIS denies the I-130. It is simply a case of proving immediate relationship in the form of a birth certificate. If you cannot prove the relation to the USCIS satisfaction, refiling will have the same result.
-Are you able to provide this kind of document to prove your immediate relative relationship with the sponsor for your I-290B filing? If no, you had better leave US as soon as possible, and do not need to file I-290B for motion to reopen/reconsideration or apppeal. That is waste time and money.
Also, if you leave and apply for immigrant visa, you will face 3/10 year bar if admission.
-If you leave US before your unlawyful presence (from the date your I-485 was denied), then you are not subjected to 3- or 10-year bar. Thuis, you can prepare the proof of the immediate relative and ask your US citizen relative to re-file I-130 for you to get the immigrant visa in China.