Problem with iPhone volume buttons?

I have the white I phone 5 and my volume buttons have been working ever since I've GOTTON this about 6 months ago…
Recently I was on FACETIME and I pressed volume up button manually on the side of my phone and of course the volume went up

Then I pressed the volume down button manually because it got a bit loud, and it wouldn't work my volume wouldn't go down unless I went into settings then to volume and put it down there…

It used to stop working then work again, but now it's COMPLETLY not working and whenever I press it nothing happens

What do you suppose I do?

See if there are IPhone or cell phone shops around where you live to get it fixed. The only other thing to do is get a new IPhone if you can't get it fixed for a reasonable price.