Can I return the New Iphone If They Refuse My Trade-In Device

I am thinking about buying a new Iphone by using a trade-in but there is just a little scratch on the case. just on the top right place, not in the screen or back glass it is around the phone and just a very little scratch and I don’t have a lot of money to spend on that new Iphone so I need that discount but if they refuse my trade-in and don’t return me the money for my old device. can I return the new Iphone I bought