Duplicate cards in iExpense

Hi,

Before we went live with iExpense, we had staff enter and assign existing cards to employees. With out first several bank files (loaded using the Visa VCF 4 Transaction Loader and Validation Program), we've had cards listed as unassigned and inactive, so we've assigned them to the correct folks only to realize later that now there are duplicate cards assigned to employees. The existing cards weren't expired or anything like that, so we aren't sure why they're being loaded this way. Does anyone have any insight as to what we're missing?

Thanks!

Vanessa