It really can be problem. You got to know your co-workers that could directly tell them what is not good work. In your e-mail to yours downline try to be patient and understanding. Commended their work, and then try to subtly tell them where they make mistakes in the work. For example, "I am very happy that I have co-workers like you. I want to be among the most successful teams in the SFI, because I think we should pay more attention to the following ...".