can I tow my 2011 with all wheels down. the manual says I can but the dealer saying no

It is never a good idea to have the drive shaft or drive axles spinning as it can effect the transmission. You either pull the drive shaft, or have the front wheels off the ground. Pulling a drive shaft you would need a spare yoke to put into the tail shaft of the trany so as to not be loosing so much fluid.

I would go with what the dealer says. If you check your manual it probably says you can tow it for short distance in an emergency. Look at what it says about recreational towing, my bet is that it says no.