Originally Posted by Panthers007

Too much torque used when installing? Those are alloy, and don't hold up as well as steel. Less forgiving to exceeding maximum torque than steel would be. On a positive note, the actual front-derailleur (FD) seems to be fine. I don't know if a replacement for the band is available. So you may be stuck with getting a new FD - but call, or drop by, your LBS and see if they have something that will work in a parts-box somewhere.

A torque-wrench and installation instructions would help you in the future.