Misleading Holiday Accommodation by Bookings.com

I book for accommodation in Durban via bookings.com for 3 nights stay. and on arrival I found that the hotel wasn't to the standard that it was made out to be. It was very dirty to a point that my son and I were not able to breath. The hotel manager called me to his office and offered me the computer to look for an alternative accommodation which I did. They couldn't refund me as they had not received payment from booking.com. When I contacted booking com and explained my situation they didn't want to refund me at first and then after 2 months of going back and forth they finally refunded me for 2 nights instead of 3. I still want my 1 night outstanding payment. This is after them refusing and lying saying that they've already made payments to the hotel. My reservation no ***