Volume and Brightness Buttons not working anymore (Mac OS High Sierra)

I bought a new MacBook Pro a month and a half ago. It was functioning perfectly up until yesterday when the volume and brightness options ceased to work. There is no response when I click the button and there's also no option to adjust my brightness in my settings anymore.

I browsed several forums for possible solutions and tried a PRAM reset, among other things, but it didn't work for me.