No sound in ear phones.

One thing to check is the ringer volume - by default you can change the ringer volume using the volume controls on the side of the phone even when the phone is locked - this often means that it can get pressed in your pocket to zero volume, which is very annoying. Try pressing the volume up button from the home screen while not playing any music and see if it goes up. You can set the volume in the settings and even tell the buttons to only change music volume, which is what I do.

when you receive a call check that the volume is turned up. it's the same control that you use to increase the ringer volume.

check around the ear piece, make sure that rubber piece is there and properly placed around the ear piece.
regards

you have 2 speakers. 1 ear speaker for calls and 2nd one for ringer, MP3, loudspeaker etc. Make sure your ear speaker volume is all the way up, nothing in the way ( dirt - make up - metal shavings etc ). If all is good have your ear speaker replaced.

Sound inducers do go bad. Normal the same audio amplifier is used for both the ear piece and the speaker. Since the speak does work, it sounds like the ear piece has died.

thebuzzer of your phone is defected, replace itand replace also the earpiece 

change the buzzer its 100% tested because ur buzzer is damage......

Hello, if your ear piece and your loud speaker are two separate speakers, then there seems to be a problem with your phone's ear piece. You will need to get it checked and replaced if necessary by a mobile phone technician. If not separate, then you would have to check your volume settings.

Yes that is a problem I see, but to be very candid it should not be related to the battery replacement, and more from getting bumped around. Did you happen to move? Nevertheless, it is usually from an internal component failure or solder break inside the phone (unless your volume is turned down, but even at the lowest level its audible). Did you happen to use a headset? Sometimes excessive tension from the headset cable will break the receive circuit you could check the solder joints. But to be candid, it sounds as if you need to send it in for repair. You can find some options by googling ... Panasonic cordless telephone repair. The kx-tc1484b is a nice phone, good range, and normally very durable, certainly worth fixing.

check your profile status and keep the volumes in high level.