While the industry settled on SHAKEN as *the* definitive method for dealing with authentication, it seems that the mobile carriers had different ideas and have implemented their own SPAM control, of which SHAKEN is just one factor. So, ultimately, SHAKEN attestation is just a "suggestion". We have seen this several times and, as stated earlier, submitting the numbers to their whitelists does seem to help -- we haven't had the repeat complaint (yet) of numbers falling off the whitelist. Of course, each carrier has their own. AT&T Wireless https://hiyahelp.zendesk.com/hc/en-us/requests/new Verizon Wireless https://voicespamfeedback.com/vsf/ T-Mobile https://reportarobocall.com/trf/ First Orion, Hiya, TNS https://www.freecallerregistry.com/fcr/