Recently my Dneice celebrated her 3rd birthday. I saw her the Sunday before her birthday (which was the Wednesday) and arranged with my brother and his partner that I would take her out shopping to pick her own present and take her for some lunch. I arranged this for the following weekend. My brothers partner indicated they might have people round for her birthday on the actual day during the evening.
I never heard anything about this on the day, but received a message from brothers partner later on in the evening of nieces birthday asking why I hadn’t attended. I replied stating that neither she nor my brother, nor any other family members, had let me know that it was definitely happening.
During an argument the following week, my brother brought it up and said I was out of order for ‘not just turning up’ and also for not messaging either of them that day to wish my neice a happy birthday (she’s 3 Years Old and doesn’t exactly have her own mobile 
)
AIBU for thinking my brother and his partner incredibly rude for saying such a thing - given that this was the day after I had taken her out and spent a fortune on her (although I concede the cost isn’t relevant as I choose to spend so much). I didn’t receive any thanks for that (should I have?)
Who is in the wrong?