Who was in the wrong?

I’m at a loss here.

I had my baby shower Sunday the 2nd and my nephew plus his mom(let’s call her L), my brother(his dad, we will call him A) brothers girlfriend, and my other nephew were invited. A and L have been working on coparenting. L knew the whole time that A(girlfriend and nephew too) were all coming to my shower and then A texted me and said they were sick and unable to make it so I told L that(we had been really good friends since I was 12 years old), and she said either way her and my nephew would be there.

Day of the shower comes, we get 45 minutes in and A walks in the door with his girlfriend and my other nephew to surprise me! They tricked me. It was one of the best surprises of the day for me because it’s my rainbow baby, my last baby, and for my first baby A and I didn’t have much of a relationship meaning he didn’t come to the shower, so the fact he came meant so much to me. It was special. Having both of my nephews and brother there.

L tells me that she’s upset with me that A showed up so she took my nephew and left. It has now been 4 days and she refuses to talk to me and won’t let us see my nephew. Somehow this is my fault, I’m to blame, and I’m being punished for A coming.