Bridesmaid issues…

I’ve found myself in a tricky situation where I’ve been hurt and let down by a bridesmaid. Bridesmaid A (one of them) is one of my oldest friends I’ve known for 20 years. Moved to Australia two years ago and we’ve kept in touch. She was meant to move back this spring, and that was the last update I had. Nov 2024, my bridesmaids (two that are organising the hen) let me know who was coming but Bridesmaid A wasn’t on the list of confirmed people. Transpires Bridesmaid A’s plans for moving back changed and she didn’t tell me. However, because of this she chose not to vote for any hen dates and deliberately stayed out of it (I was unaware of this) and then after the hen date was confirmed, she didn’t realise and since agreed to go to a rather well known festival the same weekend as the hen. I had to ask her and found out why, she open admitted she didn’t write down the hen date and basically forgot to check before she agreed. I asked her to give up her ticket in November, she said yes - then in February messaged to say she has chosen the festival instead. I’ve also found out she’s made no effort to be involved in doing any hen planning. Also in awkward position because we had limited spaces for free accommodation at the venue, and to be nice I gave her one of the two places. This was given to before any of the hen do situation came about. I’m quite upset and wondering if IATA for being upset or if this is something to be genuinely upset about? She also ignored me for a few months since November, and forgot it was my birthday the day she messaged telling me about the hen.