Pathetic an painful customer journey

Will never purchase from Zando again. They more of a hinderance than an assistance. With only a return option and no exchange item option, I fathom to understand how a business fetches a return order which was a small size item, only for the customer to reorder a bigger size. So that is fetching an item and then coming back to give the same item in a bigger size. When you reorder the bigger size item you forfeit your discount voucher as well. What an inefficient process. It is beyond my understanding and is a total inconvenience. How is your business model still working?