I don't want to deal with THAT drama

Sorry this turned into a monster in law vent.. 

We recently celebrated our daughter, Morgan's, 11th birthday.  As usual Daddy had to work on the actual day so she picked to celebrate the Saturday after her birthday. (only one day later) 

I asked her what she would like for her birthday present from us this year and response gave me a tearful moment. (not because I wasn't picked)  Instead of choosing a TV for her bedroom she picked to have a date with dad.  I almost cried because as a child given the choice of a TV in my room or any other present I would have picked a TV long before a date with dad.  Sorry Dad, I love you but it was a TV I wouldn't have to share.

She chose to go jump at Sky Zone just her and daddy.  they had a lot of fun and she didn't want her time alone with Dad to end.  Morgan ended up going to the store with him to get the groceries for the birthday dinner as well.  By the end of the day all Morgan could talk about was how amazing her birthday was.  Then the phone rang...

It was my Monster in Law.  Morgan was sitting in front of the phone and read the caller ID.  She instantly became a teenager before my eyes.  I watched as she rolled her eyes and said "Oh no, we better answer that or someone is gonna have to hear about it."  After the disrespectful way she had treated me the last time I saw her I would rather sit bare-assed in hot coals that have to listen to her fakeness.   I told Morgan answer it then.  She instantly says "No way, I don't want to deal with that drama and ruin my birthday!"

What am I supposed to force my child to speak to a person that at every chance makes them feel bad?  Just because she had her 90+ year old mother drop a bag of gifts (for all the kids birthdays.. even though Nadia's is not for a few months and two other kids' were a few months past)  I'm supposed to force them to talk to her?  What kind of lesson does this teach my kids?  That if someone buys them something they have to do things they wouldn't want to?  It's not that they wont be writing a thank you letter. (even though most the gifts were broken or not age appropriate)   I will not force my kids to be around someone that they do not want to be around. 

We have not spoken to my MIL in months. The last time she did see us she was very rude to me as she sat there in my house...  As a SAHM she was not only disrespecting me in my home but my place of work.  She sat there slinging little nasty digs at me with a self satisfied look on her face. (in front of my children)  I finally had enough an made sure she knew it.  She had the nerve to turn to my husband and say" You are going to let her speak to me this way?"  Yeah, he is.. he had enough of her drama and finally let her have it.  As she stormed out of the house she had one final comment, "What happened to my son?"  I'll tell you what happened... He's sick of being bullied by his mother and watching his family be twisted in her evil plans.. He's 33 years old with his own family and life and doesn't need an emotionally and verbally abusive mother in his life.

I could go on for hours about my psychotic Monster In Law.  Like the time we had a family counselor tell us that in all his years of doing this he has never said these words... "She is crazy.. get as far away from her as possible for a chance at a normal healthy life."  Or all the times we told her we were going to have one of her grandchildren the first words out of her mouth were about abortion... Enough about her nastiness.. I've had enough of her poisoning special moments in life.  (when I say I.. I mean we as a family)

 After not attempting any type of relationship in almost 6 months.  Should I have forced my child to deal with her and the guilt trips that come with dealing with her on their special day no less?  They have more connection with long distance relatives and with none of the bad feelings after contact. What would you do in this situation?  We chose to ignore the issue and not let it ruin our fantastic weekend. (even with her calling/harassing 6+ times)  FYI if someone doesn't answer the first time or doesn't return your call when you finally decide to leave a message, They don't want to speak with you.  Just do everyone a favor and GO AWAY!