BOOKING.COM NO PAYING

Booking.com - I am unable to revolve the problem with Booking.com not paying for guests that have stayed in our property. I have phoned and sent several mails and also get the same automated message back from booking.com. I have upheld my side of the contract but I am afraid that booking.com have not. I have googled and found that other members are experiencing the same problems with booking.com. Can anyone shed some light on this. Thank you