Caused a scene and left the free vacation with my daughter

JFYI, this is my first time posting, but a long-time stalker of the page. Before you know the actual story, I am a middle-aged woman who got divorced recently and we have been sharing the custody of my 10-year-old kid. 
My brother and his wife with their children, called me and my kid for a sponsored vacation to a lakehouse nearby so that my kid can relax a bit without any stress about her parents and bond with her cousins. TBH, my brother, and his wife are well off, and helping me out with my kid is something that I thought was sweet of them (when it's not).  

For context, I and my brother don’t get along well before, but these situations made him think about me and my kid. Now, what happened is, my brother and his wife rented out the lakeside and they paid for the whole thing with food, and other basic necessities, while I paid for the fuel for my car. 3 bedrooms with one for my brother and his wife, one for me, and another for the kids (4) with bunk beds. 

The first night in, the kids were being rude to my daughter by not letting them play with their toys but Katy, my brother’s wife asked them to behave and be nice to their sister and they did listen. Honestly, I wish she was my sister. On the second day, Katy wanted to meet a few of her friends in the town so she left my brother in charge of the kids and I think that’s the only worst decision that she could have done. It was a nightmare! The kids started bullying my kid by not letting her sleep on her bed. They wanted her to leave the room and instead, told her that she doesn’t belong to the family and she should find her place somewhere else. When I confronted them, they were rude to me too. My brother joined me and he started appreciating his children for fighting for their rights. I was shocked and asked him to behave. 

He started behaving very rudely and told me how he “paid” for the vacation and I should “obey” him for that. He also started dissing my decision to separate from my husband when I could have lived with him thinking of all the financial stability. He pointed out to my kid that she is our biggest mistake who doesn’t behave well and should learn from his ‘independent’ children. This triggered my daughter and she started crying. 

I couldn’t tolerate this and I packed everything and left with my daughter. I dropped a text to Katy as well without giving her full insight into the situation, instead told her we left because of a medical emergency. She called me after some time and I told her what happened without missing out on any points for the children too as it was necessary to get them disciplined. She told me to come back and how she will teach a lesson to her children. I said no, and told her to enjoy her holiday without making a big deal out of it. 

I get a call from my brother the next day and yells at me telling that I have ruined his holiday by ratting out his wife about the indifferences that we had last night. He got our parents involved and they bashed me for being ungrateful for the free vacation. AITA for leaving with my daughter in the middle of the free vacation?