GAP Charged for Missing Order and Issued a Non-Working Coupon

I purchased ₺17,000 worth of discounted items from GAP, which were marked as delivered, but I never received them. When I contacted GAP, they claimed the items were unavailable and issued a refund instead. However, the products are still in stock on their website, which feels like a common tactic they use.

I requested that they send the items, but they refused. Instead, they issued a coupon code that doesn’t work. When I followed up, they said the code was already used on a prior order, suggesting I create a new account to resolve the issue. This is outrageous—why should I pay higher prices and deal with such inconvenience? GAP, I demand immediate resolution and functional compensation.