Frequently Asked Questions - Form I-751
Petition for a conditional resident who obtained status through marriage to apply to remove the conditions on his or her residence.
I like your attitude. It appears to me that what is missing is proof, not genuineness. I suggest you contact a lawyer locally. They should be able to assist with finding items of proof that you may have overlooked.
In my view, failing to file an I-751 in a timely manner could cause serious problems. I think you should consult with a lawyer locally where you are.