My child is having a party and a friend of theirs was mean to them and ran off with another of their friend and left them alone for a period of time last time they played over. I came along and found my child who is 10 and they were upset so I took her with me as I was going to go out (their dad was at home too). The children arrived back as we were leaving in the car and made excuses but my child was very upset. The child who did this is a bit of a trouble maker. My child has just come to me and said she does not want this child to attend any more. What do we do? Is it ever ok to un-invite someone?