Holden Cruze 2012: Faulty transmision

I have a 2012 Holden Cruze and have been told by my mechanic that it needs a new transmission. It’s struggling to go into gear and jolting when it’s trying to. It also sometimes starts itself, the engine will turn over and then stop when I’m sitting in it with the keys in the ignition and it’s completely turned off. From reading past questions I see that Holden should replace the transmission. I have an appointment on Tuesday with them at a cost of $220 to diagnose the problem. Has anyone successfully had their transmission replaced by Holden free of charge? The man I spoke to at Holden to make the appointment refused to even tell me if the transmission was a common problem in these cars.