Fcan data bus failure

Hello
I have a same problem in my truck (Fcan data bus failure exterior lights) i have took my truck to peterbilt Dealorship they have charged me 12000 $ in repairs but unfortunately my problem is still not fixed they have put the new wiring harness they have replaced the NOX sensor they have put the new turbo actuator and now i am scared to go back to them because they are saying you have to pay us again to do further diagnostic on it and i don't have any more simply they are bandits and they say well we have changed what computer is telling us i have checked all the fuses underneath the cab and scam fuse box all of them are good i have no idea what to do
I am sitting home for almost 2 months i don’t know what to do i have payment for truck pending simply peterbilt Dealorship has ripped me off i really need help please anyone guide me so i can start working again thanks

 

No I didn’t and I don’t know how to do that

 

Don’t you think its mechanic failure and they are not doing their job properly i mean if this problem get fixed this is the beautiful truck no point of selling it

 

I did talk to service manager he said if we keep have to do diagnostics on it you have to pay us more we will not work for free i did try to explain him about all the situation that this is the message came up when i first bring my truck here and after 2 month this is the message keep coming again (fcan data bus failure) he said we have changed the nox sensor we changed the wiring harness and we have changed turbo actuator if that fails yes you can bring the truck here and we will not charge you but if its something different what we did not replace there is no warranty in that they are playing games simple is that
Money Money Money thats their main goal is looting people i was the guy who always prefer to go to Dealorship but not anymore
He gave me a example if you go to doctor he replace your kidney and you go back and your lungs fail you have to pay them again for liver transplant he said what you going to do.
Your truck is in the same scenario
After paying them 12000 when i went back to them they charged me 900 $ again just to check if everything is ok

 

And yes you are right i have recently changed my nox sensor like 2 weeks ago before i took it to them but that was from some other shop jot from peterbilt dealorship and when i asked them he said well what we did we got a message from j pro system report
I stayed quiet because i thought its dealorship they know what they are doing so i should stay quiet