For any request (the one with a 24-hour count-down timer) I'll give them a heads up a couple hours before time runs out like "Airbnb asks that I give an answer one-way or another within 24 hours. I'd like to make sure we're on the same page about *whatever issue* before accepting, so if I don't hear from you by (an hour before deadline) I'll need to decline. If you're unable to reply by the deadline, please send through another request to continue the discussion"
Also keep in mind that Airbnb takes a few days to show the most recent stats, so perhaps it just hasn't caught up to your most recent activity.