Share your experience!
My wife's phone (Z3C) is only a few weeks old, the cover over the USB port will not stay closed, it's like it doesn't fit (she uses a mag charger all the time so never opens this herself), I cannot get it to close properly and it just comes open, meaning it's not dust or waterproof.
Also, the gyroscope doesn't seem to work, if she turns the phone landscap/portrait, 50% of the time it doesn't work unless you shake the phone quite hard (it then continues to work OK for a short time), we have tried a factory reset.
Does it need to be returned to Sony? (bought through a 3rd party on Amazon)
I would recommend that you contact your local Xperia support to sort things out here. See my signature for contact info.