My question involves name change laws in the State of: Foreign

Am trying to get the correct family name put onto my son's Consular Report of Birth, but fiance was a victim of human trafficking and his information is incorrect on local records (he also has no identification in the corrected/uncorrected name). US embassy is saying to have local authorities change the information, even though I've provided documentation linking father to correct name, and local authorities are not wanting to change information. Son's birth certificate just says a boy was born alive - no name given for father or child.

Any suggestions?