How to deal with nasty BM

My husband shares joint custody with his ex. She unknowingly took the youngest to get her hair cut and it was a mess. Husband asked me to take her to get it fixed, then BM texted me ripping me a new one and telling me not to take the girls to get their hair cut because now she "can't style it and there are chunks in it." I oversaw the entire cut and there was nothing there and it looked cute. She waited 2 days to say something. I didn't respond and told my husband and he took care of it. Did I do the right thing by keeping quiet? Also, doesn't my husband have every right to get their hair cut when they are with us?