To examine these buttons we needed to disassemble the screen, which is a tricky job because of the fragile flex cables. Once we opened it, we began our detailed examination and we found out that the connections of the buttons were simply loose. We managed to strengthen them and prevent the problem from happening again in the future.
Usually a fault like that does not appear suddenly. Therefore, we talked with our client and he shared with us that he recently changed the screen of the iPhone 5c. Obviously this process led to damaging the connection of the buttons.
Once more, we managed to quickly identify the cause of the problem and our client was more than satisfied with the end result.