2008 Toyota Sienna Vibrations at Highway speed

I purchased a used 2008 Toyota Sienna and noticed that it was pulling on one side and was having vibrations at highway speed of 115-120 km/hr. The dealer did the alignment and that fixed the pulling issue but did not fix the vibration issue. So next week they did balancing and that got it back to the original issue of pulling on opposite side and vibrations at highway speed. I told them that the issue is not resolved and they were like we did the alignment and balancing. One of the sales person mentioned that all used cars vibrate at highway speeds and if it vibrates at 120 km/hr then drive at 100 km/hr. He even mentioned that used cars are not to be driven above 100 km/hr and yes its a dealership part of big Auto Group. I also noticed that they did not have any control on their service department and they would not listen. Alignment was done by new car service department and balancing was done by used car service department. Finally after arguing the manager gave me his card and mentioned to get it done outside and send them the invoice. I am thinking of getting the balancing and alignment redone. What do you think i need to do? I am in Mississauga and my mechanic does not have alignment machine.
There is another thread about same vibration issue on 2013 Toyota Venza but for him the dealer recommend him to get the Road Force balancing and i have no idea about it.