so disappointed with the service

in all of my time using this platform for bookings for accommodation i have never had issues until now a month ago when i booked the 13th of November for ATKV Goudini spa via booking.com with free cancellation in which 100% of the fees came off from my credit card. but then within 1 hour of booking something urgent came up which would make it difficult to go away the weekend i picked so i cancelled the booking which was still the 13th November. i queried when the refund would reflect. they said 15 days of cancellation, this refund has still not happened. i called goudini spa and got tossed around on the phone from 1 person to the next and no one seems to help me, i asked booking.com and they keep making excuses or saying they contacted goudini spa..... they asked me for a statement showing the payment that went off i did so...still nothing. The thing is this has still not been resolved. and this is also not little moneys that im talking about. why is it so easy to have the money deducted but so difficult to be refunded. i want an explaination along with my refund.