Bebel Sports is a large sports retailer. It purchases tennis racquets for $110 for each from A2Z Sports Goods, a large manufacturer of tennis products. Bebel Sports plans to sell the tennis racquets at a 200% mark-up to its customers. In January last year, it purchased 100 racquests. However, in April, it discovered that 10 of these racquets had design faults and it returned them to the manufacturer and obtained a full refund. Explain the GST consequences of this arrangement for both parties.