Hi Jean, I sell on Ebay. All of my packages are shipped First Class or Priority. I'm assuming if you got a pattern it would ship First Class.
When I ship from Paypal, which is always, I get a tracking number (everyone does).
If the seller cannot provide you with a tracking number she IS responsible!
File a complaint asap. That's really bad business for a seller to tell a buyer that she isn't responsible after shipping. It's total BS.
Good luck and don't worry, you'll get your money back.
Frustrating though, you want to get started on your project!