In-laws and Christmas

I need advice. Last year there was a misunderstanding as we had always spent Christmas eve with the in-laws and they decided to do things Christmas Day but we had plans. So this year I asked months in advance if Christmas afternoon works and they said yes. I then made plans for my parents to stay the night with us Christmas eve. Well now the in-laws have changed their mind and want to do something Christmas eve. I’m not changing my plans. I don’t really know what to do. I shouldn’t have to cater to them.