Transmission Noise problems of the 2011 Nissan Cube

2011 Nissan Cube with just ubder 100,000 miles was fine one day and the next barely able to pull itself. Made strange noise upon revving the engine. Had to be towed for service. Almost $4000 later I was told the transmission is Nissan proprietary and can not be rebuilt. Very disappointed that Nissan is continuing to have cvt problems. My transmission went out even though the dealership I bought the car from had the transmisson serviced at 60,000. Makes no sense to me why it would go out even if properly maintained to insure no dust or dirt got into the fluid.