@brassbracelet
Are you listing using the app or a computer? If you're on the app you can't turn off features like that. If you're on a computer you can switch from the quick listing form to the advanced listing form. There's a link on the top right of the page to switch. The advanced listing form will not force automatic relists.
Edit to add that if you have any existing listings- you will need to manually end and relist using the advanced form to disable automatic relists.