I've had this little phone over a year and it has always Auto Locked the keypad after every call. Suddenly one day, when I received calls, I could hear the caller but they could not hear me. I did a master reset and all was well......however since then I can not set my Auto Lock feature to "on". It insists on keeping it in the off mode. Changing the power settings did not help. I can still manually lock the keypad by pushing * but I have to do it after EVERY call. I can't seem to find this problem addressed online. Can someone help me? It's a cheap basic little phone but all I can afford.