I guys I have the same question, I send everything to the USCIS and I saw that they took the money out but write on the check VOID. The fee for form I-751 is 750$, but maybe I missing something. And now my green card expired this Saturday the 18th. What doesn’t mean void?? And someone now a number that I can call and ask because I cannot find any on the web.
thanks have a nice day