Answer to "Why won't my number 4 button work?"The way the keypad works on this device is that when you press a key, you connect two metal contacts which sends the information to the motherboard. If a key is not working, that means that proper contact between the two metals is not being made. The issue most likely can be solved by replacing the keypad. Make sure to visit the troubleshooting page (Troubleshooting - Keys do not work) and the keypad replacement guide (VTech CS6114 Keypad Replacement).
Answer to "Why is my phone not holding a charge?"Your phone not holding a charge signifies a problem with the battery. Simply replace the battery. If the device had not been charging at all, then there is an assortment of possible issues. Make sure to visit the troubleshooting page (Troubleshooting - Battery will not hold a charge) and the replacement guide (VTech CS6114 Battery Replacement)