I'd ignore that poster who said you like the attention - why did they click on a post asking for advice just to be mean to another member?
Going back to the email.... I wouldn't be surprised if she emails again or tries other stuff to get a reaction because you've stayed silent on it. But you've gotta stay strong and not react, and cut her out of your life!
As an aside.... I had a toxic, narcissistic family member who my mum had to cut out when I was a teenager. This family member lived hundreds of miles away but kept emailing and calling (we changed our numbers), wrote letters (including via recorded delivery so she knew we had received them) and called my school asking to speak to me! And she called the local vicar (none of us are religious or go to church) and he popped round saying the family member was worried about us and could he help mediate the family rift! We told him no thanks and to stay out of it. Eventually it did stop, but these narcissists hate silence and not getting a reaction.