Most people are getting that lag.. as far as the settlement information, it just takes time. I'd recommend keep calling and ask to speak to a supervisor to escalate your claim.. exhaust all resources.
https://jalopnik.com/2020-ram-1500-ecodiesel-fails-to-achieve-best-in-class-1838843741?fbclid=IwAR3BuxZqKHjO3Rtx9uoo4em_wYzoXQfPzVpPrFSjarrNwzQ2zhq-4vyM84s
It is pretty funny how Ram talked up a big game, but then did end up "losing". But, 1-2 MPG is not a ton.. Long live these half-ton diesel...