Distribution List Duplications and deletions

I just posted the problem with the same title.  This is a correction to that post.j  What I originally created was a contact list, with about 100 contacts.  Then I selected about 80 of them and created a distribution list with about 80 of the original 100.  It is the original contact list that had some duplications (only 8 or 9), then suffered two stages of deletions.  Further, I was never able to find the distribution list in the contact list.  Perhaps this is related to the problems.