Please check, ASAP, on a booking that Hasan says he made. It does not reflect this.
This is most likely happening because the guest is misinterpreting the quote as a booking. That often happens. When the guest gets a quote, they often believe that you are telling them that the dates are reserved. Make sure he knows that he has to finalize all the way through including renter agreement, selecting payment and confirming on the final page.
I am seeing if he has enough in his account. They tend to forget the security deposit also.