Problem with a Galaxy Mega 6.3 i9205 (phone, volume, port, battery)

[Blackandgold51]

I had a problem a few weeks ago with a Galaxy Mega 6.3 i9205(i527).

When you press the volume button for the volume to go up the volume does not go up but the volume does go down.

The outside speaker does not work and the battery does not charge.

I had the charge port changed and the speaker along with button fixed by a local shop but they said that the battery still does not charges.

The label on the phone when the battery does not charges say's it's "too hot" which the battery is not actually hot.