Judy--MOST open adoptions have a "side agreement", though it usually only has to do with contact and visitations. You can't legally make the "deals" that happen in open adoptions in most states. It's not necessarily fraud to agree upon visitation and contact issues at the time of an adoption.
The idea that it wasn't a "forever" adoption, however, makes me think that both sides were unaware of the true ramifications of a legal adoption.
Either way, it is unlikely that this adoption can be overturned.