anybody had USCIS lose their child's file?

Our son, adopted in Guatemala, came through immigration at Atlanta on 6/29/05 with an IR3 visa. Others who came through after us have already received their Certificate of Citizenship, so I contacted USCIS last week. They have no record whatsoever of our son. It appears that the sealed packet we handed to the folks at the Atlanta airport has gone totally missing. Has anybody else had this happen, and if so, what did you do? Also, if you came through Atlanta with an IR3 visa on 6/29/05, I'd be eternally grateful if you would PM me. The USCIS officer who is trying to help me is having trouble identifying anybody who came thru ATL that date on an IR3 visa, and he said if he can track at least one file, it might help him figure out what happened to our file.