I know how upsetting this can be. Something similar happened to me before, but it ended up okay.
First, you need to get in touch with her again. Is the phone number you have for her a cell phone? If so, she will not answer when she sees it is you. You need to call using someone else’s phone in the hopes that she will pick up.
If the number you had for her was at the gallery and it is disconnected, you will need to locate her personal number(s). If you can’t find the info for free, then try a site like Spokeo.com, $14.
If you have a UPS account, you can generate a return postage paid label. You can mail that to her or you could email it to her. (Instead of printing out the label, choose “print to PDF.” Then attach the PDF to the email.)
There is no value in getting upset. Just focus on your best outcome – getting your paintings back.
When you talk to her, try to be sympathetic about whatever is going on with her. If she likes you, she will make the effort to help you.