I just purchased a new 503CW and only a couple of hours after taking it home i realised the film back was stuck on the camera and would not come off. Is this because of a user error or is it something i should go back to the store/distributor for?
Usually the problem is due to the dark slide not being pushed in tightly enough to enable the small internal trigger to allow the film back release button to move freely to release the back.
So check the slide is in fully; pull it out and push it in again to be sure and help ensure the internal trigger is activated.
Sometimes some firm pressure of the back to the camera enables freer movement of the top telease button as well. Si if the dark slide tip does not help, try pressing in the back while you fiddle with the release button at the top of the film back.