Hi Rainbow,
That makes sense about her being firmer with you after agreeing about the not e-mailing and doing the DBT group. I would hope that she and the DBT leader will talk. I know with me and all these places I'm going to they want to talk to your therapist and any other person you're working with. So yeah, hopefully that will help.
I agree with Lola. I'm sure it's just as hard for her not to respond if that helps at all. Good for you for going to the class today. I'm sure the DBT people will be proud!