I can't seen to find ANY exploded drawings on red dot sights on the web.
Someone with more knowledge about how they are assembled will probably show up and post some info.
If not, I would fiddle with it to try and get it apart and then hopefully get it to a point where it is usable again, otherwise...........it's time to go shopping.
If it is not usable the way it is and can't be sent back for repair then there is no harm in trying to work on it yourself.
Hopefully you didn't pay too much for it.
I had been cured though of buying no name brand stuff years ago.
I had one of those types of sights given to me a couple years back and it sat new in the box till 3 days ago when I decided to try it on a rifle.
The dam elevation screw snapped off while I was adjusting the sight......It now resides in the garbage can.
Good luck to you, hope it works out.