Soft Key Problem.

First time I've ever had this problem, but the soft keys on both sides of the home button on my phone (Samsung S4 SGH I337) have suddenly stopped working nor do they light up. I won't take my phone apart and I can't get it sent out to be fixed because the cost would most likely be more than the phone is actually worth (Got this phone for $30.)

If anyone has any experience with this, what do you do?