Cummins Service??

Our experience last summer with two Cummins Coach Care Centers and another shop that works on Cummins was less than stellar. I am very disillusioned with Cummins shops. What was a plugged second in-line filter that Cummins should've known about and didn't resulted in thousands of dollars of diagnostic time and hours and hours of us being held up while they tried to find the problem but didn't. I found out what to look for on this forum, which turned into a $15.00 part that we bought and DH installed. Even after I tried to tell the Coach Care center about it, they claim we didn't have a second filter. Of course, the first fuel filter had been changed several times throughout our trip as that seems to be the first thing they do. After I called Freightliner and was told where the in-line filter was located and that Cummins should've known about it as they are the ones who made Freightliner install it, were we able to take it into our own hands. I have no faith in a Cummins shop.