There is a difference between a reservation and an enquiry. The clock will stop ticking once you respond to an enquiry and it will not affect you if you do not pre-approve or decline due to pending information.
However with a request to book, you need to accept or decline otherwise after the 24hours have expired then those dates will get blocked in your calendar; although you should be able to go into your calendar and individually unblock them.
If you are accepting reservation requests which are not being passed on to the guest then you should contact Airbnb as not only does it affect your ranking eventually, you are also losing potential business. Click on the link for contact options - Contact Airbnb
Hope you get it resolved soon too,
Ama