Help with marriage certicate for immigration!?

My aunt got marrried in Guatemala and 1984, so now her husband is us citizen and he is sponsoring her. The marriage certificate that shows they were married in 1984 is old so when she went to her interview to the US emby they asked her for a new one, well she went to get it but the system changed they only have computers now and the new certificate came that they were married in 2001, Oh my God what she can do, a lawyer is asking her for $2000 to fix the error. Do she can call immigration to fix the date on the application or pay the money. please help any advise , do anyone knows something about this?