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You could try chargeback if you've given up on the idea of ever getting the order fulfilled.
You could try contacting them using the web form if you haven't already, that's probably going to work better than just emailing them. If you still want the thing but not if it's going to take forever, give them a firm deadline to deliver or refund.
If you've tried both of the above without result, you can use the Small Claims court service online.
Depends a lot on how you paid