I would not have been embarrassed, but embarrassed for her.
Who else but JW's use the word "apostate" as a condenscending label?
No one else but you saw that word as a bad word.
Anyone in earshot of those comments were likely wondering if your accuser skipped her meds for the day.
If you wanted to really have fun with it, then wiseass comments can go a long way.
Make sure to say these comments loudly like you were speaking to an 85 year old deaf person:
"Have you found it harder to live in this world that *pause* Jeho-vah will soon destroy at *pause* Arma-geddon?"
"Are you still following the voice of the, *pause* Governing - Body?"
"Yes, I'm still *pause* 'an APOSTATE'. Are you still part of the *pause* GREAT CROWD? How's that working out for you?"
Use their own freaky, cult language to make an ass of themselves.
Then turn around after talking to her, shake your head, and say barely under your breath, "Too bad your still in a cult".