You're never actually "selling" the item. No money is changing hands, because it's all staying with you, since it's your item. How could money change hands if it was your item before you started this process and is still your item afterwards, but there was a "purchase" transaction?

You're not buying an item and reselling it either. You are intentionally listing items to "buy" yourself, using a different account, and going through a site that offers cash back on transactions. Since these aren't actually real transactions--no money is changing hands, then I'd say you're running a scam.