Something you might find useful, is that you can block incoming calls based on the calling number on CME.
Here is how i would block 0894110000 from being able to send its fax-spam
first create a voice translation rule to match:
config#)voice translation-rule 1
cfg-translation-rule#)rule 1 reject /0894110000/
apply this to a voice translation profile
config#)voice translation-profile blockSpam
cfg-translation-profile#)translate calling 1
finally, place this on your incoming dial-peer NOT with the normal way of applying a translation profile but with a special command called call-block
config#)dial-peer voice pots 100
cfg-dial-peer#)call-block incoming translation-profile blockSpam
cfg-dial-peer#)call-block disconnect-cause incoming call-reject
I hope this helps someone out there, Once when I first started in the VOIP industry I inadvertently helped someone setup there router to send fax-spam. I guess this is my attempt at forgiveness and help you work your way around it!