@Kyle476 I can't imagine why CS told you to post this issue here- nothing wrong with doing so, but no other host can assist with getting this moved onto your review page.
I've read of this happening before, but I don't think there's anything you can do about it. It's so unfortunate when a guest wants to praise your place but misses the review window or thinks they're posting a public review, when they're sending you a personal message.
In the future, you might send a reminder to guests you feel will leave a good review when there's only a couple days left to review. They get Airbnb reminders, but they might not look at those. Of course, you wouldn't want to be a pest, but one message like "Hi XX, I've written a review for you and see that you haven't submitted one yet. Would really appreciate it if you did so, but I realize you may be busy. Just a reminder that the review period will run out in two days, and it's not possible to submit one after that. Thanks so much for booking my place and being such a nice guest."
You could use what Alexander wrote as a photo caption, maybe, if it's okay with him. "Private message I received from a guest: XXXXX".