Diesel treatment is one thing.. if you're not in a cold climate and the artic blast hits (like Texas this week), then you must treat the fuel yourself.
We'll, keep us updated. Hopefully the dealer can source the parts from somewhere. It seems EGR/emission components in general are hard to get right now due to COVID-19.
Welcome! It's possible the oil change was done outside of the the dealer. A lot of folks do not like the "stealer ship".
Perhaps YOUR first service is free, not talking about the truck itself?