Of course they can do that, so long as you............................
Pay their over inflated price, or
Buy it on their finance package which will never end, or
Take a totally derisory offer on your p/ex , or
Sign up to a service package that means you'll pay a fortune for what amounts to an oil change, or
Buy it on a PCP deal which will means it's not really yours unless you want to get raped at the end of the deal
Take your pick