Technically this is not an airline complaint. The companion certificates, although issued to be used on Delta, are issued by AMEX. Delta has nothing to do with these except for the fact that they are redeemable on Delta and have Delta's logo on them. I have requested to have this thread moved to the "General Discussion" forum.
I have an friend here in Phoenix who has a friend (merely an acquaintance of mine) who works for AMEX Travel. I'll ask him if he knows anything about the Delta AMEX and the companion certificate. I know my parents have had the Delta AMEX for a few years now but have only used the companion certificate once! I'll be visiting them in November...if you want I'll nick theirs and send it to you!