Last month, I went through a very rough patch with my SD and her BM.  Sprouting from me asking my SD why she was sent home from school (for verbally threatening some girls).  I received very nasty, almost abusive texts from BM.  And I did respond diplomatically once and only once.  This resulted in a further abusive email response and I then blocked mommy dearest (as i call her).  Later, I reviewed the response and decided to write a response but not send it as there is no point in doing so.  It was more for my own sanity.