Bad Return Policy At Baby City

I bought a Doona cup holder from Baby City Tokai today under their product advi*****t and when I arived at my car a minutes later, I realised they gave me the wrong Item. I immediately went back into the store to return the Item and I was told that they do not give cash refunds, only a coupons. I mean they are the once that sold me the wrong item in the first place, now I am stuck with a useless voucher. They should have their return policy written in bold at the door to alert customer. They are really desperate for customers.