It's just not a priority for her.  I'd send her a text or something that says please return my items by xxxx date, I can pre-pay postage if you would like, in the event you do not I will be filing a small claims action against you for the cost of my property in your possession.  Then sue her if she doesn't return them.

Or just write the whole thing off.  It's kind of up to how important these items are to you.