(((((((lynn)))))))

this sounds like an awful situation to have to deal with and i'm sorry it happened to your daughter. at this point i wonder if backing off might be better. it seems the mother and kids are blatantly trying to upset you and your daughters, so by not responding to their baiting you will not be encouraging their inappropriate behavior. it does seem when you respond in any fashion they end up escalating things. because they are getting a response they see they are upsetting all of you, and are relishing it, and so continue doing it. if they get no response from here on out they will likely decrease their behavior over time because they won't be getting the response they want.

i say this as someone who was teased for all of 3 days in high school. i don't know why some kid decided to pick on me in homeroom as i'd never been picked on before. i completely ignored him and didn't respond at all and after 3 days he was bored with it and never bothered me again. internally, i was pretty freaked out but i didn't let it show at all. it takes 2 to have a fight so if you bow out then they will hopefully just leave you alone eventually. my concern if things continue as is for your family is one of you is going to start getting restraining orders or contact lawyers and this is going to be an even bigger mess.