To be to blame for plans I was not told about?

[ponderywondery]

It was my In Laws turn this Xmas, they came to stay at ours for a week and then we entertained some friends for a few days. We organised to go to my parents on one day between 25th and new years for xmas. My sister and family stayed with my parents for the week. Other than the one day Xmas with my family, no other plans were communicated with me, in fact I thought my sister was only up for two days.
Mum has sent me lots of messages asking when we are coming over to play with kids. I’ve explained that I didn’t know about their plans so we can’t make it as we have other plans. My mum has said she’d just join our plans. None of our friends can stand her as she tends to dominate everything and be rude. So I declined in a polite way, often saying we’d already booked things or that we were already out.
Mum has said that she needs to rethink Xmas for future years, with the implication being that it’s my fault. Well, more than implication, she said I was depriving the children from playing together and she might not do Xmas at hers in future. I’ve explained that she and my sister need to tell me if they make plans as we would have organised to see them, if we had known but we can’t change our plans last minute (we’d booked shows, outings and things ages ago in October and asked them then, if they wanted to do any of it but they declined as they said they didn’t know what they were doing etc).
The kids saw them today as a compromise even though it’s the only day we have as a family before we go back to work and I’d rather not have.
AIBU? Should I have cancelled my plans?

When your mum tries to emotionally blackmail you by saying that she probably won't host Christmas at her house any more, just say that's OK and that your in-laws will be happy to host you.

Her behaviour must be awful if all your friends have spoken to you about her, as normally people would just keep this to themselves, unless the behavior was really bad.

Thanks. Thats good advice.
Yes, she really is bad. She’s offensive and rude to people and meddles in people’s lives including giving unsolicited financial advice (she’s not a financier) and bullying people into doing what she tells them to do. Multiple friends have said they’d rather not spend time with her.

Don't go into defensive mode. You did nothing wrong. Just say "don't host dinner if it's a problem that's fine"
If she doesn't get a rise out of you she's not gained anything

"Sure ok"

Mum has said that she needs to rethink Xmas for future years, with the implication being that it’s my fault.

Manipulative, Narcissistic, attributing blame.

Don't rise to it. She is looking for a rise out of you, and an argument, and for you to bend and sway to her whip. Don't play the game.

Ok then, if not hosting works better for you then that's fine with us, we accept your decision 🙂

Something else will be said to initiate a rise, but watch for it and you'll start to see the poke poke poke

You've explained why you couldn't change your plans. If she says she's not hosting next year, just say 'ok mum, that's fine' and leave it at that. Don't rise to the emotional blackmail.

I’d reply with “okay. We always have to juggle things and plan ahead of time so the sooner we know the more likely we can plan around others. Appreciate you didn’t feel it worked this year so we can change things next year.”

wrongnpost

She's trying to manipulate you into panicking and grovelling. Don't. Stand your ground and say OK don't host then.
Do what works for you. You won't get these Christmases while your children are little and everything is magical back, so don't waste time on her making you feel this way and do what works for you.