You can set up ads to be seen only by customers who have already contacted your business. To do this, create a customer contact list and use it as a data source.
As contacts, you can use the email and phone numbers of customers that they left when they bought, or the id of users that you collected on your website or in the application.
To collect data for a new audience segment, you can use a counter Top.Mail.Ru. Learn more about how to do this