Trendyol/Köfteci Yusuf Order Discrepancy: Incorrect Weight & Refund Denied

I ordered from Köfteci Yusuf through Trendyol. I ordered 540g of bacon and other items. Later, the store representative called to say they only had portions weighing 300-350g. I agreed to accept what they had and asked for a refund for the difference. They sent only 388g of bacon but charged me for 540g. When I requested a refund through the Trendyol app, it was rejected. They then asked for photos, which I provided, yet the refund was still refused. They apologized, but allowing customers to be deceived and then apologizing isn't acceptable. I won't deal with Trendyol or Köfteci Yusuf again. Neither of them acted ethically in business. The difference doesn't make me poorer, but apparently, they need it more than I do.