Yeah, one of the things you could really say to them that they’d actually care about (because clearly they don’t care about your feelings) is, “you really embarrassed yourselves today.” And don’t even bother to elaborate.

I would say that usually these people do escalate until they get a response from you. The trick is to grit and bear all of that until they stop. They have to truly believe that they will not get a response from you no matter what they do.

One option might be changing your name?

I wonder if it would be possible to go talk to a cop about the situation and see if the cop would be willing to sit down with the grandparents and explain this to them. There certainly are reasonable cops out there.

She doesn’t want to rock the boat. Afraid of conflict.

There’s a book called “set boundaries, find peace” you might find helpful. Very how-to/example-oriented.