2ndGenREX

Parents have a 2002 honda civic EX coupe. The eletric key chain with the automatic lock buttons sounds like it works when you press them, but it doesnt. Car beeps when u press button an lights on car flash and car does signature honda beep beep but the doors dont automatically lock like they are suppose to when u hit the button. Tried changing battery in the little keychain keylock and still not working?? what do i do