Nissan Dualis 2010: CVT gearbox quality issues

I have major concerns with the quality of my 2010 Nissan Dualis. The CVT gearbox is getting worse, but I have been told that the decision maker at Nissan is away, so no action can be taken until his return. In addition there is a gap between the headliner and windscreen, but I have been told that unless the fault in the headliner can be seen from outside the vehicle or from the seats then the fault is to be considered normal. I have already had the headliner replaced once, as well as the rubber seal on the driver's door after it just fell off. The driver's door window is now rubbing the tinting off and the window is marked rather badly. There is also a rather bad oil leak, which I suspect is from the transmission as the oil is red. I now also have concerns with the quality of the seats as the driver's seat is showing bad signs of wear after just 32,000 km. I noted my concerns to the dealer some time ago. I have previously owned three Nissan X-Trails and they have been a pleasure to drive, so I am at a loss as to why an English-built vehicle can have so many issues. What can I do?