The Constant Contact Database Comparison feature is used to compare the email addresses in Constant Contact with the ones in eTapestry. In some cases when the Comparison is run it returns incorrect information.
If any contacts were deleted from Constant Contact they will still appear in the integration because they aren't ever fully deleted from Constant Contact. The comparison does not filter them out of the results. This is documented in our Constant Contact Integration Best Practices. If you have not deleted any contacts/emails from Constant Contact, contact Support and reference this article.
In the meantime, export lists of email addresses out of eTapestry and Constant Contact and compare the two columns in Excel in order to get some of the data from the comparison.