Booking.com Pay at Property Issue - Hotel Demands Unauthorized Payment

I booked a hotel room in Udupi, India through Booking.com with the “pay at property” option and no advance payment required. However, the property representative is calling me and asking for an advance payment. There is no mention or instruction about submitting any advance payment in the booking rules and regulations, yet the property person is insisting that I pay in advance or they will cancel my booking.