Well, it definitely sucks that they aren't doing what you want. Maybe they have a better idea? Or maybe you need to send them to their corner until they learn to behave. Either way, THIS is a big part of why we prep. It's good to discover these things now rather than in the middle of NaNo and it all goes off the rails.

Look at what's happening and see if you think it's a good idea. It seems like maybe you don't. Is there another character who is supposed to be the bad guy, but you haven't discovered it yet? Is there another plan you haven't noticed? If you can't see how this is going to work out right (not necessarily according to your original plan, but to become a good story), then look back and see if you can spot where things went wrong and see if you can chart a different course.

Good luck!