Bernabe,

There isn't much to discuss here, you obviously have an engine problem and the ONLY solution is for the dealer to replace the entire engine under warranty. There is no reason for the dealer to fight you on this, because it's the Nissan manufacturer that pays the bill, not your service department. They actually make money on warranty work because they bill the labour time back to Nissan too, so it's win win for you and the dealer.

This is not the time for any more discussion, normal engines don't use oil when they are new, and even when they're several years old they should NEVER use even close to as much oil as your Rogue is using.

So the one and only course of action is to be persistent with your Nissan service department, which shouldn't take much effort because it is obvious your engine is complete crap. If for some reason they don't agree, all you have to do is put in a call to Nissan USA or Canada (not sure where you live), and they'll follow-up with the service deparment and make them take action. The oil consumption is documented, so the facts are plain as day and the course of action is very clear.

Also, if you can visit or call a Nissan service department in a neighboring city I'd highly recommend that, chances are they'd compete for the chance to perform the warranty work because as I said, they make money on the labour.