When I make a call the person on the other end can't hear me? On two of the phones Eco message next to the battery on the screen.

Not sure if this is the same as your Problem, but
I once had a problem with an iPhone where the person at the other end was responding, but they couldn't hear me. I Think the rain got into the microphone hole on outside of the phone during a severe storm & I needed urgentt help cause of the rivers flooding around me. (NorthWest Oz).
Murphy's Law - a phone will always break down when you need it the most!
As a temporary fix, I simply switched over to the speaker phone. The other person could now hear me OK.
(Use the hands free switch on the screen to turn the speaker on)
The iPhone has 2 microphones and it appears that only 1 was functional. It uses the second microphone in it's noise cancelling circuit. I guess it compares one input to the other to cancel background noise.
Anyhow, the iPhone came right the next day after drying out.
Hope This Proves Helpful to Others as well

Your phone is dying. Next your screen will go out. Get numbers off your phone if you plan on changing carriers

turn up your volume

If you can fixed it, fixed it by yourself by replacing a new speaker.
If not please refer to the nearest mobile service to solve your problem.

Thanks for using FixYa!

Put in dry rice in warm airing cupboard for a few days. If not working carefully open and try again. Or try a hairdryer not too hot!

You cannot turn off the ECO mode manually.

Intelligent ECO mode (select models)
Power consumption is automatically reduced when the handset is close to the base unit for extended talk time. Battery life on Talk is up to 13 hours when in ECO mode.
https://panasonic.ca/english/telecom/telephones/features.asp#eco

I would delete all paired devices from the Parrot kit and delete the Parrot kit from your phone, then remove your battery from your phone for 5 mins, then repair as a new phone. If this does not work you have a microphone issue, check the wire is not trapped behind one of the trims.

can't hear the message & don't know how to make it louder

Called the company. There is a misprint in the instructions.

In the section titled "Out-Going Announcement RECORD" on last step it says Press Exit to stop recording. It should have said Press Sel/Save.

I did this and it worked.

Repeat for Line 2 if you are doing both lines.

Next thing is to make sure you go right to the section titled "Configure Out-Going Announcement" and select the right type of message you want callers to hear for each line.

Worked like a charm and took 3 seconds to get 2 different personal messages on the machine.

Go to a skilled mechanic, request him to check the charger, the charging connector, the charging controller IC to solve the problem.

Supriyo DG