Nmom keeps inviting herself for Xmas

We just had a baby in the fall of last year. I told her that we didn't want any long term visitors for a while until we figured out new schedule out. She goes ahead and books her and dad a flight out for 2 weeks over Xmas break. I made it pretty clear last year that I wasn't very happy with this. Nmom is a very bad alcoholic and I have a lot of resentment built up over the years. Dad drinks a lot also but he doesn't try to hide it like she does. She has bottles of vodka and wine hidden all over the house. She is a nasty drunk. I think it's the sneakiness and the attempted hiding of it that pisses me off more than anything. Contact between us is minimal and usually through text. Every once in a while I get over ridden with guilt and will call or FaceTime. The last couple of face times, she has been so drunk that she can barely speak and keeps repeating herself. She decides that she is going to go ahead and book a flight for her and dad again this Xmas! Doesn't call to ask or check dates and just goes ahead and books the tickets. I'm absolutely fuming that she is going to ruin our favorite time of year for 2 years in a row. I have already said that we won't be having good any Xmas dinner at our house this year and that my sister will have to make other arrangements for them. Nmom knows I am pissed and hasn't contacted me since. I don't want my child being anywhere near her but I feel I am obligated to let them have a relationship. If I don't, she will use that as a reason to drink even more and tell everyone who will listen that I won't let her visit. The thing is that there has been no major event or blowout that would cause me to cut off all contact but it is something I think about doing on a daily basis. I feel like my life would be so much more peaceful without her in it but then I would have the guilt of making my other family members have to listen to the extra shit from her. I dunno, maybe it's just easier to keep the act up instead of telling her to go fuck herself and her manipulative bullshit.

End of vent.