Remainder alert

Greetings of the day…!!!
I had given the task of risk management. I have an excel file where the supplier detail with mail id is provided. Based on Priority I should select the supplier and send them the mail to fill the form and send me back. Once I received the assessment I should scrap the data and write them in excel. Till this I had done. Now, After 3 days I should send the remainder to the suppliers who did not reply to me the assessment form. How can I achieve it? I am completely blank can anyone guide me.