Engine Exhaust System problems of the 2005 Infiniti FX35

Vehicle began to exhibit white smoke on start up through exhaust. Brought vehicle in for service, was informed that a cleaner and some parts were required but vehicle was ok to drive. Upon waiting for parts, experienced more smoke and then engine noise. Immediately stopped vehicle, checked oil and found oil level too low to continue. Returned vehicle to dealer, waited and was informed that after 40k miles, vehicle required new engine. We have been waiting three weeks for Infiniti to warranty the engine. They have requested service records, but will not make a determination to warranty the engine.