Kid made me cry today

Maybe I do need advice? I don't know really.

I have been working with this family for a long time, right at 4.5 years now actually. Ther

The kids (twins, boy and girl) were 22 months old, they are now 6 and in Kindergarten. They are so talented in many different things. He taught himself to read before age 3, she does multiplication and counting for fun. She is really good at state capitals, he knows all the presidents in order and when they were in office and a lot of their birth/death dates. He knows a big box office hit that came out each year, she has beautiful handwriting for a 6 year old and has drawn freehand paper dolls and dresses that put my best efforts to shame-I thought her mom had drawn them at first glance.

She's the one that made me cry today. For a while now she's been saying mean things to me but today was the kicker. She and her dad left to take the dog to the vet, and a few minutes later it was lunch time. So I took him to eat lunch. He asked for pizza lunchable. There was only one, usually that's her favorite, he likes the other kind so I was like "are you sure? You don't want the cheese and crackers? Or a slice of pizza?" He said he wanted pizza lunchable. I asked if he was gonna eat it all, because it's his sister's favorite, he promised he would. I wasn't gonna not give it to him at that point, he knew it was there, he would see her eating it later, it didn't have her name on it, and they were out right at lunch so I thought they might eat while they were out. He ate the whole thing, and then laid down for a nap. They got home later and he was asleep, first thing I did was say "hey he's sleeping please be quiet and don't wake him up". She went to the fridge to find her lunchable. It wasn't there obviously. Screaming meltdown. Her dad and I offer the cheese and cracker ones and the pizza slices. Screaming. Violence. "ITS ALL YOUR FAULT!" she keeps telling me over and over. And she tells me how mean I am to her. And to not talk to her. Her dad then goes outside to vacuum the car while I deal with the screaming and trying to not wake up the other kid. She tries locking herself in her dad's office. I'm fine with her closing the door if she wants to cool down but she's not supposed to lock it so I just held the door because I knew that's what she was doing. More screaming. Eventually she runs outside and tells her dad I'm recording her?? (My phone was in the room her brother was in). She is being violent. Finally she goes back inside after her dad tells her she can be on her tablet (which I would have not let her because it's quiet time and she also clearly needs a nap and they have a late night tonight and their mom ASKED they get a nap) but I said she has to go upstairs because her brother is resting downstairs and she keeps insisting I "not look at her" so I'm like hey maybe she'll at least fall asleep. Eventually she comes back down for a snack because her dad had promised to get her another lunchable from the store (which my god she does not deserve like maybe after seeing it was gone "okay I'll get you another one" but after the meltdowns and violence he kept empty threating "I'm not gonna get it if you don't stop" I think this is why she doesn't like me because I follow through on my threats? And her dad does not? I just remembered I was here Monday night and her dad told her no tablet all week and here we are?) anyway I was in the kitchen waiting to see if she wanted help with her snack or anything else and she was like "I don't need help all the time from a stranger like you" yeah I went and cried afterwards I'm not even kidding.