How/When to "fire" external designer

yo, exactly. However I find that I am a “difficult” client as I am a designer myself and as they mentioned, they have never received a thorough design brief. This means that their other clients are unprepared (oh these marketing teams…) and therefore they may accept anything that “looks nice”. Those may be the easy to please clients.
FH13, this is what i plan to do. If this time also does not work though I am thinking to try to give a very specific direction regarding ideas, style, even sketch out a direction or give them similar logos (something that may sound insulting to a design professional) and see if they accept another round of revision in this way. If it is ok, I may continue just for a week to see how is progressing. If not, then we stop the collaboration ( I will let them know of course that this is something that may happen). In this case though I will loose a good amount of money but that is life. I hope I got my lesson as well.