I can't turn of this handsfree thing in my phone..

During phone call, do you see a 'speaker' icon you can press in the screen? It only shows when a call is active. It toggles between handsfree and fry-your-ear mode. If you are listening with the loud speaker and plug in your wired headset it will automatically go off speaker mode (takes a couple of seconds to work). You can put it back into speaker mode while the headset is still attached.

On mine, it remembers the volume I last used with the speaker, so if you had the volume down you can adjust with the up-down buttons on the right hand side of the handset.

If you have an older storm, I think the volume buttons have sometimes been reported to have problems. Whether you can fix that will depend on whether you are under a service contract for handset warranty or maintanance.