Sony MDR1A doesnt work properly

ok so i couldnt find my actual device here but its sony mdr1a. when i first ordered it, it was working perfectly fine but then the left ear (where you connect the aux) started cutting out. I tried the other aux that came with the device and it worked perfectly; for about a week. I can’t connect to other Aux cables, because it has a very specific port (after the thin part, like the neck has to be slim to fit) and i havent found a single aux that goes all the way in & authentic sony ones cost 60$ on amazon! if you know what the problem easy please help and also theres no tutorials on how to disassemble it online so help would be appreciated! Also the left part makes squeaky sounds when you turn it around