Air Bag Not Deploy problems of the 2015 Infiniti QX60

We purchased a new 2015 qx 60 infinity in may, 2015. We noticed when my wife sat in the front passenger seat, the air bag light went on indicating the air bag would not deploy in an accident. During the 6 month servicing, I mentioned this to the infinity service dept. And was told they would reset the sensor to zero. They also said that if the system thought my wife was a child based on her weight, the airbag would be turned off. After the service the problem continued. During the 12 month servicing, I again mentioned the issue and was told there was a recall on the sensor. Three weeks later they called to say the qx 60 was ready. When I picked it up they again said if my wife was less than a certain weight, the air bag would not deploy. Now the seat belt light is on all the time whether my wife is in the vehicle or not. We were not aware or informed of this issue prior to buying the car. It makes no sense that an infinity air bag will not deploy with my wife in the passenger seat when there has never been an issue on amy other car we have owned. To me, this is a significant safety issue.