Good for you!!
I would not take my baby either. I just got my first yorkie pup and have waited for many many years to get her. There is no way I would let people do that to her. I'm glad you are standing your ground and if they ask why you are not there, just tell them. I would make sure they understood how you felt about it because I am sure you don't want to avoid every dinner they have frome here on out.
Hope things get better
Mandee