Shopify is a hosting platform and not really responsible for individual transactions on it's host stores.
Your basically showing up at a closed store in a mall and asking the mall to fix it.
Though you can still contact firstname.lastname@example.org directly
Depending on payment method(paypal,a credit card etc) contact your issuer to try and get it fixed if your seeking a refund.
This is May from Shopify.
I'm sorry to hear that you have not received your order yet. Like @PaulNewton mentioned above, although we provide the platform for businesses to sell their products online, we don't actually manage their day to day operations such as sales or shipping. If you haven't already, I highly recommend checking our our FAQ: Your Online Order page for next steps. We take these cases very seriously, and we really appreciate if you take these steps, as it will help our Operations team gather more information about the store. If they do operate on our platform, our team can use the informations you gave us to run an investigation if one take place.
Let me know if you have any other questions.