Booking.com 'Free Cancellation' Turned Refund Rejection at Hotel Millennium by Acon

On June 29, I made a reservation through Booking.com for Hotel Millennium by Acon, with reservation number 4828425893. Both the hotel's general information and room details clearly stated "free cancellation." Due to personal reasons, I had to cancel my reservation on the same day. After 12 days without a refund, I contacted Booking.com customer service, who confirmed I had an unreturned payment. When searching for the hotel, the first page advertises free cancellation to attract customers. Despite selecting a standard room and the site stating free cancellation until July 2, they're now using different explanations to deny my refund. This raises doubts about the accuracy of hotel information published on Booking.com. We've seen that they can surprisingly contradict what's clearly written on their site. I'm requesting my refund be processed as soon as possible.