When Attache BI is setup with ezyCollect, the first sync will bring across all customer contact details.
The main contact in Attache BI (found in customer/details tab) will be the tagged in ezyCollect to Receive all Communications by default and this will be recipient of automated ezyCollect communications.
All other customer contact will not have any tags in ezyCollect.
To tailor specific customer contacts to receive different automated communications in ezyCollect, please check our Customer Contact Tagging and Advanced Communication Workflow Settings.