I agree, I do think ignoring could work, but if she doesn't let up or continues to contact your Dad or anyone else in your family...

I think YOU need to tell her...

"leave me alone, please do not contact me or my family".

You could also add "good luck with the rest of your life" or something like that, but I think you should keep it short so she doesn't get the wrong idea.

If she continues to try to contact you, you could threaten to get a restraining order which would forbid her to contact you and also to contact you through anyone else (that's how it is here in the states, I don't know if the same rules apply in Finland).

I do think you should be the one to tell her, by text, e-mail or snail mail, I wouldn't use the phone.

The best of luck to you!