Automated Email windows service c#

Hello, Need a desktop application (WPF) that will allow my users to upload an excel with user data (name, email, dob, etc...) and on upload it will add only new data. It will keep duplicate data the same. Data will exist on a database (SQL) because multiple users will have the application and be able to upload on their personal machines. The user can also manually update/delete the row data if need be. The windows service is to send an email to those customers from the database that dob falls on that date. It will send at a specified time on that day just once. I also need a sent column that lets the user know if the email was sent for that day.