Confirmation number 3419.906.813

I made a booking through booking.com and wanted to add another person for the accommodation, but it was too expensive so I canceled the booking, the place I made the booking for the accommodation sent me an email saying they will not charge me any cancellation fee, they understand my reason that I will not book an extra room for a child that is so expensive and that I can get cheaper accommodation with more benefits. The problem is I don't hear anything from Booking.com, they simply don't answer me. When I made the booking there was an option of pay now or pay later, I chose later but they still deducted half of the booking from my account and now that I have canceled they just don't come back to say when will i get my refund it makes me so angry...