money held hostage

I made a booking for accommodation though airbnb booking site. The booking was cancelled from their side and the authorisation of my payment was supposed to be voided by them. this has not happend and I cannot get the direct contact details to take this matterup with them., The email addresses used in the confirmation of booking is not valid if you try to reply. According to my bank there is still a reservation on this money and airbnb needs to contact the bank directly