Car brokedown after being taken for a service at the dealership

My car experienced issues with the gear box the day after the driver took it to Nissan The Glen for a service. We had never experienced any issues whatsoever conveniently the next day the driver couldn't drive the car as it couldn't get into gears. Gladness advised that the part that was broken, now 'replaced' doesn't come loose however the mechanic was able to replace the broken part, this sounds like a temporary solution to me, she even asked we check if the problem still persisted. I would like the entire system to replaced as the car is still under warranty. To this day I am awaiting a call from Gladness regarding confirmation of the warranty period, she advised incorrectly to say the Nissan's warranty period is 5yrs/ 100k KM according to my knowledge it is 5yr/ 150k KM. What was disappointing is her lack of feedback.