HW Topic 1.2.1 Writing formal and informal emails

Write an two emails one formal and one informal on thr topic of Follow-up on Unpaid Invoice

Scenario:
You are responsible for managing accounts receivable at your company, and one of your clients has an overdue invoice. Write an email to follow up on the unpaid invoice, politely reminding them of the payment and offering assistance if there are any issues delaying the payment. Be clear and professional, while maintaining a courteous tone.