If your buttons are sticky, the numbers are worn off, or the keypad is malfunctioning, simply clean or replace it.
Be sure cell phone is off before you begin to disassemble the phone.
Press the button on the bottom of the back of the cell phone.
Slide rear panel down and remove it.
Using your fingernail, pry the back of the battery upwards and pull out.
Insert the plastic opening tool under the faceplate.
Separate the faceplate from main body by twisting the prying tool with some force.
The faceplate is held by three plastic fasteners, so pry evenly on both sides of phone.
With the faceplate removed, simply peel off rubber key pad and remove.