Listening on a call is tinny

Deb, most likely the tinny sound would be solved by replacing the earpiece. Sometimes the very thin membrane can become torn due to dirt or debris touching it, the only solution is to change it. However it could be some small fragments of metal which would be attracted to the magnet in the earpiece, a gentle brushing over the earpiece may sort this, however most times its easier and more successful just to replace the part.