@Johan1153 When you receive an Inquiry message, that is just a way for guests to contact hosts to ask questions or clarify things. Guests may have sent out inquiries to several hosts, trying to decide which place to book.
So it's not at all unusual for hosts never to hear back from the inquirer. It would be nice if they at least thanked hosts for answering, but it seems many don't have polite manners.
When you pre-approve an inquiry, the guest has to go on to make a booking if they want. It isn't like a Booking Request- if you accept those, the guest is automatically charged and if the payment goes through, the booking is confirmed.