Hi,
Look at the pfBlockerNG-devel Reports page. Look at the Alerts and DNSBL lists. Look for the IP your device us using, and then a destination that should have a relation with this "sagepay " (whatever that is).
Note : Feeds used by pfBlockerNG are created by humans like you and me - most often 'just for fun and to help the community'. They could be useful for some one, contain IP's that shouldn't be blocked for others. It's NOT an exact science.