Chosen Solution

At first it just goes all the way up itself and the ringer keeps showing on my screen. Now the ringer’s gone from my screen but I couldn’t turn up the volume by pressing the button. The volume down button works well. The headphone jack, mute and charging port work fine. What could be the problem and how can I resolve it? Thanks!

Its either a problem with the cable, which would need replacing, or there is dust or dirt built up behind the up button that needs clearing out. either way it looks like it will need opening unfortunately. does the up button physically click still, or does it not appear to move? that would be a good indication of which approach to take.