Mother of my daughter's friend isn't allowing them to play together, saying nasty things about our family

About a week ago my 8 year old daughter had a friend over for a sleepover. Let's call the friend, Lila. As the girl's mother was dropping her off my 17 year old daughter came into the kitchen and grabbed some coolers I had bought for her. Her and her friend were having a few drinks while getting ready to go to a party later that night. I know not everyone is ok with their teens drinking in their home but it's a decision I have made and I'd appreciate if that was respected as that is not what this post is specifically about. The next day I received a long email from the mother of Lila stating that she thought it was disgusting that I would let my older daughter drink and that she would no longer allow her daughter to be friends with mine. She also said rude things about the way my teen daughter dresses, called my husband a "pot smoking hippie" and took up issue with the fact that he has tattoos for some reason.Now I could understand her not wanting her daughter over here if my teen daughter was drinking in front of the younger kids or around them, but they were in the basement and the woman's daughter and my eight year old were in her room two floors up!Now my daughter has came home from school saying Lila has told her "my mom says I can't play with you anymore in class at recess etc." Apparently Lila has also said things such as "my mom says your mom is a dumb rich gold digger" "my mom says your family are drunks" and other things. I'm assuming some of these things are getting misconstrued as most of them don't really make sense, but I'm still appalled that a mother would say bad things about another mom to her child! I also heard from another parent that Lila's mother asked the teacher to not sit the girls together or have them work on projects together. Lila and my daughter were good friends at school and got along well, my daughter doesn't understand why suddenly they are not allowed to play together and I don't know how to explain it to her. I'm also not okay with this mother saying negative things about me and my parenting to her child or other parents at the school.I'm at a loss as to how to handle this. I've never had to deal with anything like this before and I have no idea what to do.Edit: To clarify I did not provide alcohol to the other teen. She had brought her own provided by her mother. The mother knew she would be drinking. Also I'm aware that in the states underage drinking fines are common but that's almost unheard of here, a teen caught drinking would be asked to dump it out and sent on their way. The idea of cops lurking at houses looking for underage drinkers is preposterous to me. via /r/Parenting http://ift.tt/2eEntmQ