Hi,
I've had this issue as well...and as I new Host, I was looking forward to getting Reviews on my place. I was told that there is a strict 14 day policy and after that time, Reviews can not be written.
My guest inquired as to how to write a review and I also was trying to do it for my guest. We either did not receive an email or we missed the email and now after 14 days, there is nothing that can be done and no reviews can be written.
I just spoke live via phone with AirBnB Help Desk and they said that it is a black/white policy under Review Guidelines that they MUST be done within 14 days of the stay.
Lastly, they did say that if you don't receive the email...but you are still within the 14 days, then you can go to your dashboard and under Reviews you should be able to do it.
?? Strange and frustrating to say the least.