I'm seeing this more and more in forums. Someone orders something from an online shop, then never receives their item. Sometimes it's a legitimate reason and the seller got a huge number of orders and is getting them out as quickly as they can, but unfortunately, sometimes it's also a case of just a bad seller. This doesn't mean you're out both your item and your money, however. This will focus mostly on Etsy, as that's where I have most of my items listed and do the most business besides my website, but will contain some info on eBay as well.
First, Contact the Seller
First of all, try to contact the seller. If it's through eBay, Etsy, or another venue, try to contact the seller through their messaging system as well as email. If you paid by Paypal, check the details in your payment and see if there's another email address listed there and try that one as well. eBay will also supply phone numbers with the order, so you can try to call them. You can also check Facebook to see if they have a business page and leave a post there. If you've made several attempts to contact the seller and have received no response and seen no updates on your order like a shipping notification, then it might be time to move onto the next step.
Most selling venues have a limited amount of time that you can open a complaint (or case) with them against a seller. On Etsy it's 60 days and on eBay it's 45 days, so watch your calendar closely and don't let that time expire before taking action.
What if They Try to Just Cancel the Order?
If a seller tries canceling a sale on Etsy to keep you from opening a complaint against them, you will have about 48 hours from the time they submit the cancelation to leave them a review on the sale. If there was a processing time on the order, and they cancel it before that time has passed, you will not be able to leave them a review. If the review window is open, however, and you get an email saying they've canceled the order, then I would suggest getting a review up as fast as you can. Once the transaction is canceled, the review will remain, so other potential buyers will see there was a problem. If you paid for your item through Etsy's Direct Checkout, the seller has no choice in refunding you in full as Etsy processes the refund as soon as they cancel the sale. If you paid by Paypal, Etsy only asks the seller if they refunded and a seller can easily mark "yes" even if they didn't, and Etsy will allow the seller to send the cancelation request through.
How Do I Get a Refund if I Paid By Credit Card?
That being said, if you do not receive your refund from the seller through Paypal, you still have some options. First, contact Paypal and open a complaint for "item not received". You can do this two ways. First, find the transaction in your account and click on the "Details" link. On the next screen, scroll down to the bottom and there will be a link that says "Report a problem with this transaction". Click on that and follow the steps. The second way is to call Paypal and provide them with the date of the sale, amount, and who it was sent to so they can find it in your account and start the process. Paypal allows 180 days from the date of purchase to file a complaint on a transaction.
Another option, if you paid by credit card either through Paypal as a guest or through someone's website and their own payment processor is to contact your credit card directly at the number on the back. Some credit cards will only allow 90 days, others will allow as long as 6-12 months to file a complaint. Again, here, you're going to need the date of the sale, amount and who it was paid to.
A legitimate seller will answer your emails and either let you know why your item is delayed or when it should be shipping out. I keep a whiteboard calendar in my workroom with all of my orders tracked on it so I know about when I'll be working on each item. When someone contacts me and asks for an update, I can find their order very quickly and tell them within a day or two what day I'll be making it and when it'll ship. If a seller isn't holding up their end of the transaction and seems to be stalling you, then make sure you take the steps to protect yourself and secure your refund.