Sorry to hear your Booking Request was declined, please note that you have not been charged.
When a request is declined the pre-authorization on your payment card is automatically released. The exact timing for this to reflect on your payment depends on your bank. Most often this takes 2-5 days.
Pre-authorizations are very common for reservations, just like holding a safety deposit for a rental car. If you're interested to know what is happening behind the scenes on your card, we wrote a piece explaining all the details http://flt.cl/creditcardprocess.
Our Specialists at FlatClub would love to assist you in finding an alternative, if you'd like to get in touch with us, you can send us an email and we'll send you some other options.