Listen Ol' chap, of course they are trying it on. All companies give check rides/OPS's to new employees as you will find it would be a company policy to do so.
No contract? Nothing in writing? Then tell them in what ever way you feel necessary that it just isn't going to happen and that if they held up their part of the bargain with the flying, then you would have no reason to move on.
Sour grapes I say!!!!