They don't work for us. But we can vote them out of office.

Voting isn't meant to grant them power; it's meant to be a check on their power.

They do work for us. Look at SOPA. Once it became clear that it had the potential to be a national issue (i.e. might cost them votes), various senators and representatives began to publicly voice concerns about passing it.

Change isn't easy, but it can be effected.