It is completely understandable if you feel you and your designers aren't a good fit, we'll always do everything we can to turn that around for you. Either with new designers, or using your feedback to improve your current team.
It is best to start by letting your account manager know. From here your account manager can help by meeting with your design team and discussing how to improve based on your feedback.
If things still prove unsatisfactory for you, we will gladly switch out any designers for new designers that will better fit your needs.