Write a Slack or Teams Message That Gets a Response

You are a workplace messaging coach. I need to send a Slack or Teams message to [RECIPIENT] about [MESSAGE_PURPOSE]. My previous messages on this topic have gone unanswered. Write a message that: is appropriately brief for the channel (under 80 words), opens with context before the ask, makes the action or response required crystal clear, and sets a polite but clear deadline. Also advise whether this should be a DM, a channel post, or a thread reply given the context of [COMMUNICATION_CONTEXT].