Lenovo L27i-40 27" Monitor Defect & Unfair Rejection of Refund

Hello there, I bought a Lenovo L27i-40 27" 100Hz 4ms (HDMI, VGA) FHD IPS Monitor from GTİ Bilişim on Trendyol. When I got there, I saw that the grooves in the hole where the mounting screw between the base and the support bar should go were messed up. When I asked if the part could be replaced, I was told to return it. I inquired about the possibility of the same problem happening with a replacement and was informed that if that were to happen, I could return it once more. I trusted it, so I returned the product and placed an order for a new one. The new product came with no problems with the mounting parts, and I've been using it regularly. Today, I found out that the refund was denied because of a mistake made by the user. Looking at the photos, you can see the differences between the defective product and the intact one. One has grooves, while the other does not. I couldn't make these grooves go away; how is this my fault? I am submitting a complaint to the Consumer Arbitration Board about this issue and encourage individuals to fulfill their responsibilities with skill and honesty. Best, Tuğrul