Inceptions
If you received an item that is not as described (in your case, an empty envelope), you have up to 30 days to open a return using the option next to the transaction in your Purchase History. The seller will have 3 business days to provide a prepaid return shipping label or else refund (save the envelope in case you need to return it). If he does neither, go back to the case on day 4 and use the option to ask eBay to step in. They will force the refund.
