Booking.com not as secure as they promise

I cancelled a booking well within the time period and received confirmation that it had been cancelled free of charge. The venue (Troutways) irregularly charged my credit card two months before the proposed stay. At first they disputed the refund and then promised to refund. After two months I have still not received my money back. Despite all promises by Booking.com that bookings are secure, they have made no effort to assist me in getting my money (R840) back.