Your niece is getting married.
You ADORE your niece.
You have been estranged from your sister, her mother, for a few years.
You're completely okay with this as you've decided the less time you spend together...the better.
You received an invitation and RSVP'd for you, your husband and your two children.
The morning of the wedding you get a call from your sister.
Your sister tells you that she doesn't want you and your husband at the wedding but that your two children (early 20s) can attend.
How do you handle?