Question about refund to a guest


We had overbooking on 13-14.08, contacted hot line about it.

A guest reservation number 2876020103 hasn't arrived at our place because we didn't have any rooms available that day. Now she is waiting for refund, but we cannot cancel her reservation as it is not visible on her page anymore. She is calling our hostel and texting us on booking.com

Could you suggest please what shall we do in this situation, because she's paid with her virtual card.


Hostel Zappio