Our leads in Marketo are pulled through Salesforce.
When we send an email campaign, we often upload a specific list of people so that we have the correct targeting. When I upload a list, I select untrusted source and do a default (fast import).
Currently, we have the first name and last name set as blocked fields in field management. The idea is that we want to send an email to this list of people, but they already exist in our database and we still want to record the activity on their records.
Lately, I have noticed we have a lot of duplicate records. And the duplicate record is being created through a list imports that I am doing.
How do I upload lists and still record the activity in the contact records, without creating duplicate contacts?