Multiple users?

First things first I'm using cs-cart 2.1.1 Had a strange thing this morning. I was getting ready for a mass mailing using my own mailing software. I exported the user list to csv. When I import into my mailing software it tells me about any problem addresses. I told me I had about a 12 - 18 duplicate addresses. We use email address as user id. I checked several addresses in the admin side, shows no duplicates. I used phpMyadmin and look at cs-cart_users table sorted by user_login, no duplicates there either. So I'm guess that the export of users must of had a hiccup. Anyone had this before? Next thing. While in phpMyadmin in the cs-cart_users I noticed several records with out user_login and password in a row 7504-7507 and 7510. After a bit more looking I notice that these did not have any addresses in the user_profile table. I resorted table by password and found the two record missing in the previous series 7508 & 7509. They do have names and other info. They showed a user_login as user_7508 & user_7509. but no password. Is there something I should do or be looking for? Thanks for any help, David