Had to cancel my booking because of booking.com and pamuzinda hotel and conference in benoni

Am so angry you inconvenienced me last minutes left before check in...i had to cancel the birthday party as I was asked to pay extra cash for breakfast because they said booking.com under charged me imagine... on the day of check in I recieve that message if you were me what would you have done? I thought you guys were reliable but no even the manager there said no there's nothing they can do as it's booking.com fault so my question is where do I fit in there? Because I booked got the confirmation email with prices and benefits include but on the day of check in around 1 I recieve WhatsApp telling me that at 2 when I come I must come with an extra R360 for breakfast on the day of the booking because booking.com. under charged me and it's their fault as per the hotel.