Reseller – Coupon code abuse

Hey all,

We had an incident recently with our eCommerce Shopify store where a few orders managed to use a 50% off coupon code. This led to various people buying a large amount of stock on our site & then they started undercutting our main listing by a few cents on Amazon stealing a lot of the volume / delivering a poor experience.

Is there any way we can block these seller or remove them from the listing?