They provided me a new IPhone which had a slight m...

They provided me a new IPhone which had a slight marked on it, arranged a collection for the phone and then claimed I have personally marked the phone so not prepared to replace the handset, not even been turned on or plastic covers removed, seen the mark immediately once I removed the phone from the box
they claim once the box is open they cant be returned, how can you see if the phone is ok until you open the box, but arranged a collection anyway.