Can't find access code

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I ordered something as a guest and it turns out I have to return it. In order to print my shipping label I have to enter my email and an access code (I didn't need the access code to process the return request). I cannot find an access code anywhere in any email sent to me from ebay. I created an account with the same email (the account I'm using now) in hopes that it would retain my information from the order and I would be able to access it through there but that did not happen. I've tried using the item ID, the return ID, the email reference ID, the generated name that they gave me in the email, and the transaction ID but none of these are working (they all have too many characters). Shouldn't there be something that says "This is your access code"? I didn't receive anything like that. Thanks for your help in advance!