Nick here from Shopify.
Could you let me know the name of the popup you are using please? Once we know the name of the app, it will give us the insight needed to remove it from your store completely. If you could also share your store URL or a screenshot of the popup, it would be a huge help in troubleshooting this for you. Looking forward to hearing from you!
I don't see the screenshot anywhere in your reply. Would you be able to attach it in a reply here please?