Hello @HRKeeper. You can contact our Support team who can review what options there are to remove the incorrectly uploaded contacts. In the meantime, do not take any action within the Contacts area, including uploading or removing a list. Due to the weekend/holiday, they will not be available until Tuesday, June 20th.
There needs to be an easy "undo import" option beside each import listed so that users are not dependent on tech support to address this. This feature is available in MailChimp and is one of many examples where Constant Contact is not keeping up with basic features.
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