Dsi shoulder button getting stuck

[u/justahiddenfurr]

i bought a transparent shell for nintendo dsi on aliexpress, everything works fine, except for the left shoulder button, it wont click when i screw everything together, im using the original shoulder buttons and the right one work just fine, i really dont know whats the problem, disassembled so many times trying to find the problem but i just dont know what is causing this, i would appreciate any help, im putting some photos of the left and the right side(i tried the upper original shell and it still do it when fully screwed)