THY Damaged My Luggage and Only Wants to Cover a Third of the Cost

On April 29th, I made the mistake of flying from Japan to Izmir with THY. Upon arriving in Izmir, I learned that my luggage would be delayed. When my luggage finally arrived via courier, it was delivered broken. I had purchased the luggage a week before the flight for ₺2000. When I submitted feedback online, my claim was rejected because I hadn't filed a damage report at the airport, as my luggage hadn't arrived on time. Later, my feedback was reconsidered, but the issues continued. When I took my luggage for repair, I was informed it couldn't be fixed. THY initially accepted this report and requested my credit card statement but then claimed the report wasn't uploaded to their system. After persistent efforts, my compensation claim was processed, but they offered only ₺700. They rendered my brand-new ₺2000 luggage unusable and offered to cover only a third of the cost. It seems the remaining two-thirds is considered a penalty for choosing to fly with this company. I objected to this offer. Now, they have been stalling for a month without providing any response.