Don't worry, mai nahi bataoun ga Laadli jee ko. 
I am really not sure what wrong could have been with the button. It might be due to some dust or may be the contacts on the board have weakened by time. We face a similar problem with the Remote control's buttons of a security system. So you should better get it checked. The real experts would be in a better situation to provide you an authentic answer and solution. 