Hi, as others have said, need to engage with one of their other units to get this sorted out - as a network provider, their customers are relying on YOU to access their service, PSN should care.
technically, you could start looking at netflows to the PSN and see if anyone is engaged in DDoS via that route...and , if you offer IPv6 native service to end users, ask PSN when they are going to be offer an IPv6 service to their users - so this CGNAT stuff can go ;-) alan
