Can I 'return' a licensed photo and get my credit back? I realized too late I already have it.
You can't double licence, except if you push “licence again” in the licence history. Don't you think that you only “redownloaded” the asset?
If you feel, however, that you re-licenced the asset, I suggest you contact Adobe customer care. Adobe customer care can be contacted by beginning a secure chat session at https://helpx.adobe.com/contact.html?rghtup=autoOpen. Pop-up blockers need to be disabled! If the chat window fails to open, or is non-responsive, use a different device to start the interaction.
Support phone numbers may be found here: https://helpx.adobe.com/contact/phone.html. Please note that phone charges may apply.
(see also here: https://community.adobe.com/t5/creative-cloud-services/how-to-contact-adobe-support/td-p/11875703 or here