I’ll admit that after editing the {user}.ini file directly the client was able to see the licence in the UI, so i’m hesitant to touch this any further in case I accidentally break their account access.
In regards to their account: this happened following a funnelback upgrade so from 15.6 => 15.16. I can’t speak for the specifics of how the accounts were migrated across as I was not part of that process but I presume it’s part of the normal upgrade process.
In any case this should be resolved as client can access their licence.