Need help and some advice

Hi, I'm new to the forum and i have an issue. i just bought a new to me 2010 2500 st and the dealer pulled a fast one on me. after all the papers were signed and i got home i finally noticed the truck has been deleted (nox and dpf). i never noticed while at the dealer and they never told me. I checked the truck out pretty good before i signed the papers and what thru me off is the original downpipe and tailpipe and muffler were used so you could not tell the deletes were done until you slid under the truck or put it on a rack(i was unable to do either). now the problem is they sold me and titled and put a plate on a truck that is 100% illegal to drive anywhere in the country. so what should i do? make them fix it? Make them take the truck back? Make them pay for the missing parts? i know a lot of you already run your trucks this way, but i feel that it should be my choice to remove and my legal responsibility. please give me some advice.
ps the dealer turned out to be complete a holes after the fact, and were not willing to fix a minor problem i found on the drive home.