I'm Ann, from the team here at Shopify :)
I'd love to help take a look into this, however, the steps on how to remove this will differ depending on how it's implemented into your store. Can you show me through a screenshot, share your store's URL or tell me more detail how this message was added (through a banner app, in the product description, etc)?
Once I know more I can try to suggest the best option!
Have a great one,