Sometimes when a customer fills his cart and proceed with checkout when the page is open he is not able to select "Register" or "Buy as a guest" because the form is hidden. It is not at all in the page. Does anyone know what may cause this issue?
We have a promo code for free shipping - one usage per customer is allowed. If this promo code is used by a guest user, he is given the free shipping - which is OK. But if he enters the site again and tries to purchase something the promo code is "auto" applied. He do not need to enter anything. Seems like the browser somehow knows that this session has entered a promo code before. Where the promo codes usages are stored?
I understand what we cannot restrict the usage a promo code to 1 per customer if he is not registered, but ins't there a way to validate the usage based on shipping email not by customer email?