What should I be doing now? (It's done)

[Coconut]

Ok, so Stbxw text'd me back yesterday and I would like an opinion of if my text was inappropriate, spiteful, or what, cause I thought it was just straight forward and fair pretty fair way to say I was upset without adding any comments about why I thought she did it or without being spiteful... But she obviously didn't see it that way.. Do I need to work on being more neutral? I'm curious what y'all think. So the original texts were:

M - I'm very upset that you, knowing we have a Christmas party every Christmas night, made plans for son to go to grandparents for dinner rather than spending time with his dad.

W - I didn't make the plans, my aunt is in town &I asked to do dinner on Christmas night. I will ask my mom what we can do. I'm not even sure when I'll get to see him at this point.

End of original texts. A little context I'll fill in, everyone at that dinner will be off work and in town for the week after Christmas, and my Stbxw will have him Christmas morning.

Next day:
W - I know you think I'm this horrible person but I spoke to my mom & she said son can go to your moms Christmas night & we will do our family Christmas another night. Instead of sending me a text like that, you could simply speak to me about it so we could work it out but I know you'd prefer to take the hostile route. Enjoy Christmas & you're welcome.

M - I wasn't being mean, I was upset and I said so.

W - K