If this was an expensive camera, the seller might not have wanted to deal with the hassle of a new buyer as they do tend to be riskier (not necessarily you specifically, just in general), or he may have broken it, lost is, sold in on CL and forgotten, etc, who knows, not important.
If the Seller realized after payment that he didn't have the order or for the above reasons didn't want to ship it, he should have cancelled the order. If you didn't receive any notification of cancellation and refund, the seller didn't do it yet as he stated. Check all of your communications and look for it. In most cases, you'll be notified of the cancellation before any refund hits your bank.
If the order truly was not cancelled and no refund processed by the estimated delivery date, the next step would be to wait until the estimated delivery date has passed and then file an Item Not Received case (one day after that date).
![Video [Russian Language]: Answers to common Payoneer registration issues](/t5/image/serverpage/image-id/750612i41F587DBC26EF24C/image-size/large?v=v2&px=999)
