The Find duplicates query wizard should have worked just fine, while I like jmiskey's approach too, though I try to make queries fully "visibly" defined in the query builder because I fairly rarely view the SQL (though sometimes you have no choice). (And until that post, I didn't even know there WERE properties on queries. It took 4 tries for me to find them!)
Anyway I suspect your duplicates really aren't duplicates. If you think there are 12 records for company "Gulf Oil" in field [Comp name] in the table, try this test. I'll base this on the query builder but you can work straight from SQL if you want. Start a new select query, make your only field
"<" & [Comp name] & ">" and run it. Then rerun it after hitting view/totals. The difference between the two results should reveal something - perhaps impelling you to get busy with Trim or Upper or something.
The acid test would be doing the above test with this sole field:
"<" & [Comp name] & ">" & "<" & [Contact] & ">" & "<" & [Secondary cont] & ">" & "<" & [address] & ">" & "<" & [state] & ">" & "<" & [zip] & ">"
Unless you misused the wizard in the first place, I don't think that jmiskey's approach will get you any further. (And again, jmiskey, your advice is always fine.) I suspect you'll want to try something like the technique I've shown. Hopefully it will help you get a "better handle" on the data, or point you to a better definition of the duplication "definition."
Considering the chances of those particular 6 fields being spelled, nicknamed, 5-digit vs. 9-digit, etc. EXACTLY the same ... I'm not at all surprised that the duplicate query found nothing.