Hello, I bought Sony WH-1000XM4 headphones in unknown condition. It turned out that the right side, the speaker and the touch panel were fully functional. On the left side, the buttons, NFC and indicator light work. The only biggest problem is that there's no sound from the left speaker. I tried to connect to the computer via aux and again, sound could only be heard from the right side. What could be causing this problem? I would be very grateful for your answer.