Cross Border Fees on my bookings with Booking.com

I made 3 bookings in March 2024 with Booking.com through the app on my phone. One was accommodation in the Strand, and a booking for a vechile. The other was accommodation in Somerset West. When I received my Nedbank Credit Card statement there were Cross Border Fees charged for all 3 bookings. I live in SA, my bookings were in SA, payment was made with SA Cedit Card. Why the internatiinal costs? I have contacted them numerous times, sending them ALL the information they request .... they keep on coming back asking the same information. I am not getting anywhere with them. I need the Cross Border Fees paid back to me.