Today I think I broke someone's heart.
In what way did you break their heart?
I ignored the calls and messages she sent me
You should apologize and be honest to people if you don't want to be with them. It is good to be upfront with people and not ghost them.
I'm hoping she will get over it. She should since I'm not going to apologize.
It's upsetting that you won't apologize, as ghosting is wrong and it makes people feel awful. Being honest about not wanting to date or be with a person is the right thing to do and you should be mindful of other's emotions and feelings.