Write a Payment Reminder -

Dealing with customers who are past due on their accounts is one of the most stressful circumstances for a business owner or entrepreneur. It’s a fine balance to ask for payment in a polite yet strong manner, but it can be done. 

You should send a reminder notice informing the customer of the amount outstanding and how they can pay. If the customer does not pay by the deadline, you should send additional mails to them. In general, there are three letters: an initial notification, a forceful reminder, and a final demand.