Need some advice !!!

My husband and I have full custody of his 8 year old. Her bio mother contacts me when it's convenient for her to ask about my sd. A part of me wants to be nice and tell her how she is or etc. However a part of me what's to tell her off because she wants to play pretend mommy. She hasn't seen her in over 6 months. However we did let her see her brothers in November. I'm tore because she as other siblings by her bio mom. However when the custody battle went down bio mom made it about herself instead of my step daughters feelings. Bio mom has no visitation rights or rights to her at all.