Wiring problems of the 2006 Nissan Maxima

Nissan of middletown replaced drive belts, air filter, & changed oil 12/1/08. (I requested the original drive belts to show my husband as I never recalled having this service done on any of the cars I owned at such low mileage. ) on 12/5/08, my 2006 Nissan Maxima (approx. 37,900 mi) just stopped on a two lane highway. I was pushed off the highway, opened the hood, checked the belts (which were fine) & noticed fresh battery acid spewing from the battery. Towed to mechanic in town who had the car for 10 days in which time he changed the battery and said the battery wiring harness had been damaged but still thinks it is something else as the car would start but wouldn't run. Car was towed back to middletown Nissan and they immediately found the problem - the mass air sensor was bad. They replaced the sensor 12/15/08 and told me that these things go bad. I contacted Nissan headquarters and stated my concern that this happened after the maintenance work had just been done. After review, Nissan repaid me $426. 25 for the sensor. I continue to have concern that not only must I now replace the battery wiring harness at a great cost which the local mechanic estimated the part at $700 plus labor, but also when I stated that my car just stopped, without warning--no service lights, nothing (what if I were on the thruway doing 65 mph and lost power - engine, steering, everything -- with no warning-- I'd probably be dead along with any passengers) Nissan's headquarters verbally reported to me over the phone that a car is mechanical and these things can happen. Well, I'm not satisfied with this response. I still question what happened to my basically brand new car when Nissan middletown did the maintenance work on it. I would appreciate your opinion on the mechanics and the safety of this vehicle. Thank you for your time and assistance.