I dunno, I'm find myself to be a volatile personality in general, so on any other day I would have deleted all their project files and told them to take a hike, but I've made enough enemies recently so I'm trying to control the part of me that wants to hideously mess everything up for them. Unfortunately it seems I can't win.
Anyway, update, I told them any further revisions to their finished mixes at this point would cost them money, because I have other work to do and they didnt seem to like that very much, they seem to think I possess unlimited time to waste of them for apparently no benefit to myself. There's so many inconsistencies to this project that its a real botch job, tracked far too quickly and really messy. I gave them chances to retrack months and months ago, but they were too lazy and pulled the "fix it in the mix" attitude, and now they're complaining because I can't actually fix botched guitar tones etc in the mix.
Basically everything has went wrong with this whole thing that could, I've learnt a lot though, I guess this is the traditional audio engineer trial by fire. If I still find the will to mix after this one then I'll have completed the first test or some bullshit like that.