booking.com dont stand by their promises

Made a booking for accommodation in 2020 that was clearly advertised as refundable if cancelled on November 11 2019. The booking for $420 was cancelled on November 15 2019 and booking.com notified. They responded that it would take 10 to 15 days to be refunded. It is now 20 working days and still no refund. Each time I query this the response is it will take another 10 to 15 days to get the refund. Do not use booking.com