I am sorry for the troubles. Please see the FAQ article below for issues syncing with the Forerunner 610.
What can I try when my ANT Fitness device will not sync with Garmin Express?https://support.garmin.com/support/searchSupport/case.faces?caseId={600f3dd0-3e6a-11dd-d7af-000000000000}
If you continue to have trouble please contact Product Support by phone.