How to write Reminder?

Hi forum members,

I really want to send email politely but cannot writing it. Please advise me:)

I send e mail to counterparty and somehow I didin't receive any reply yet.

I've already sent three reminders, so now I'm wondering they could receive my mails

In this situation, how can I send 4th reminder mail?

In this mail, I want to Inclue below questions.

1. Make it cleat that They could receive my mail or not

2. if they do and revert it to my team mail adress,I want to receive it to my own email adreess to check If our mail system has issue on receiving mails.

3.request them to reply it ASAP

Many thanks and want your comments too:) thank you again!