Not being paid by Booking.com

Guests have stayed in our accommodation  having booked through Booking.com. I have all the details of their stay as provided by Booking.com, including Admittance Advice. However, these same periods show as 'no activity' in the finance box and we have  not been payed! Staff at Booking.com I have spoken to, and  messaged, agree I am owed the money and say they will 'deal with it' ( I have copies of their emails etc) but a lot of time has now passed,  but still no payments! 

Has anyone else experienced this? 

Alastair