There's always a way to take things apart.
Putting them back together so they look like they haven't been apart is (sometimes) the tricky part. I've serviced many 'non-servicable' gadgets, quite often needing as little as a button-cell replacement.
It helps if you have a kit like this, though... (the 99pc "Not So Common" bit set from Lee Valley)..
99pc not so common bit set flash.jpg