The lies are killing me

So to go into a little of the animosity between me and my nephew's mother. She lies! My dad (who never said anything mean about anyone) would always say "you know when shes lying because she opened her mouth."

On little man's night before first day of school she called me after he was in bed and told me she got a call about a foster placement that needs her. Not like her own son doesn't need her or anything. I hung up in tears because first off what will this do to little mans mind. My mommy and daddy won't let me live with them, but they got another little boy now. He's sleeping in my bed and playing with my toys, but I can't be there...unfair. He already has enough emotional problems without her adding on more.

It also broke my heart because we gave up the idea of fostering to adopt to make sure he was provided for. He is very demanding on time, and it wouldn't be fair to him or another child to do that to them. Needless to say I was beside myself with what to do. Over the next 3 days she told me tales about how her husband (my brother) worked so hard to get the house clean and passed a home study. She told me the child was suppose to be dropped off that night and I had to hurry and get her home. They don't have a vehicle, and I am the only one willing to drive them around.

I told her my concerns on the way home that night. The next day she tells me that foster boy didn't get dropped off and will be after school that day. Then she tells me that night that she changed her mind. So I go to check her phone records. I manage my brothers finances and their phones are on my plan. There were no calls received anytime around the initial phone call from the social worker.

SHE LIED ABOUT IT ALL.

This was the final straw for me. I messaged my brother and asked him about the home study and cleaning. It never happened. I told him that she never even received a call from a social worker, and he defended her. After a few hours of back and forth. He tried to tell me it wasn't all a lie. That he didn't want me to confront her. This makes everything so much more difficult for taking care of their child.

I told my brother that i would talk with her only about stuff to do with little man. Other than that she was out of my life. No longer allowed in my house. I am beyond done with this ridiculousness. She's told lies in the past, but never once this so intentionally hurtful.

Do you think I over reacted? What would you have done differently in this situation?

This is another one of my paintings. Hope you enjoy.