Left joycon wont connect or charge while in handheld mode

I dropped my original joycon and it broke the shell, so swapped them out for both joycons. My right one works perfectly but the left isn't detected when it is slid into my switch, it won't charge either.

I tried to see if there were any problems with the ribbon cables inside but they all looked fine and the prongs on the joycon where it should connect up look fine too.

In wireless mode, all the buttons and the joystick work fine but it just disconnects when attached.

I thought it could've been a problem with the actual port in the switch so i bought new joycons to test it out. They both dock and are recognised fine.

My knowledge of fixing tech is very limited, so any help would be greatly appreciated!