So I bought a pair of Sentry Studio Stereo Headphones from Big Lots for $10. I've currently had them for a week. Well, my problem is, when I plug them into my phone (or anything really), to listen to music all I get are the instruments, not the singer. It's very difficult to listen to Fall Out Boy if I can't hear them singing. What could the problem possibly be, and what happened to make them do that?
There is a problem with your connection. If you look at a headphone jack it is broken up into three sections which represent ground and an A and a B channel. Your symptoms indicate that you are missing one the the channels. So it's either a problem with the headphone jack itself or you have a broken connection in the head phone.