Cannot enter voicemail password

[cdeuel]

When I go to check my voicemail or enter a number during a call from a list of options nothing happens.  I know how to bring up the pad, but it doesn't ever go through I could just sit there and press buttons all day long.  Very annoying.  Please Help.

[M91-30]

perform a hard reset by shutting the phone down, removing the battery, pressing the power button and holding it down for 10 seconds, then let it sit for 15 minutes. start up the phone, and it should work. if not, perform a factory reset by going into settings, privacy, then factory reset (or whatever it's actually called in there). when this happened to me, a hard reset worked just fine.