get a linkedin premium for trial and inmail one of the top level executives.
There's really no excuse for a 5 month old customer facing ticket with real notable amounts of money involved. I'd be sorely embarrassed, and it appears they are.
At the very least they need a sensible way to separate issues involving real money to be in a different priority bucket with actual escalation.
My time should now be deprioritized?
I ended up speaking with one of their board members.