Refund request

I have made a booking on Booking.com for a stay at Umhlanga self catering guesthouse in April and paid a 50% deposit fee straight to the guesthouse account which was given to me via WhatsApp . Due to other commitments in June I cancelled the booking and requested a refund, i sent the lady i was liaising with on WhatsApp my cancellation too, after no response for a while she said all communication must be made via booking.com. I started emailing them via the app as she advised and sent through POPs as requested. 2 weeks ago they said they are actioning the refund, to date nothing has happened. Now they even blocked me on WhatsApp. Can hello peter assist me on this matter as i am now frustrated