Other than using shims to plumming and leveling the door, there really isn't much else to do. Perhaps the jam casing is 'twisted' kinda like liquorich if you know what I mean. Just make sure you plum and level the door. Maybe the door(s), itself, are 'twisted' or not properly mounted. I guess it's possible to have the jam plum and level but NOT the doors. Check that. If this is the case, talk to your 'supplier' about what to do. I'd insist they be returned. Again, the key is that the jam is plum and level.