Manifold/header/muffler/tail Pipe problems of the 2012 Nissan Murano

I purchased a 2012 Nissan Murano new, my vehicle has less than 22000 mileas on it, no services lights have ever come on to indicate that any service was needed to be peformed on the vehicle. I had an oil services done, however in one of my oil services done recently something occurred incorectly and my vehicle starting blowing smoke from the mufflers, again no warning lights ever came on to indicate a problem or maintaince was required. I took it in to the deaslership service center and I was told that the engine had major problems, they told me that for the engine to be as damage as it is warning lights should have come on. They also said that they have seen a few more vehicles with simialar problems and the warnings never apperaed on those vechiles as well.