Don’t know where to start. In short, they’ve blacklisted entire IPs on our ASN. Such a mess.
Either it is an extortion, or something wrong with their algorithm.
Random check to our IP addresses (yes, we got a lot of them), reveal none has been blacklisted by another RBL except by UceProtect.
Fortunately, after monitoring postfix log for several days, it seems that many postmaster has disabled UceProtect for their RBLs.
But still, it’s annoying to see that record on MxToolBox.