You understand that you have the right to privacy and even if you allowed her access to you phone, it wouldn’t end there. It’s a slippery slope and there’d be the next demand to violate your privacy. So it’s good that you said no.
Here’s an article on boundaries that might be validating, in case you wonder if you should bend to some of her demands.
https://bpdfamily.com/content/setting-boundariesTake a look at the Tools section at the top of this page. Keep reading others’ accounts and posting more of your story.