"Why won't my ear pieces stay in place?"に関する回答Try lubricating the extension and the plastic piece holding the pad that cushions the top of your head and see if that helps the adjustment slide. If not, it might be a mechanical problem. You can check out the slide adjustment repair guide and hopefully it works!
"Why is my microphone not picking up sound?"に関する回答Check that you're not muted on your computer. If that doesn't fix it, you can also check if the controller is faulty by testing the microphone with another program. Is the problem is still there, you probably have to replace the microphone jack <LINK HERE>.
"How come sound only comes from one ear?"に関する回答Make sure that the headphone is fully plugged into the audio jack, you'll hear a light click if it's properly done. If you think the speaker cone needs to be replaced, check out the speaker cone replacement guide.