Turkish Airlines Luggage Wheel Issue and Response Email

During my THY Istanbul to Sivas flight, I received my newly purchased suitcase with a broken wheel. Upon arrival at Sivas airport, the staff there documented the issue and promised to replace the suitcase. Since it was my first flight with the new suitcase, I preferred to get a refund. The staff directed me to customer service with a report. However, customer service responded via email stating that the suitcase was already broken when handed over to them. If that was the case, how did the staff document the issue? Previously, I couldn't get a new suitcase due to a similar problem. My suitcase was genuinely damaged when I boarded the plane, and they refused to document it during the replacement request. Now, they claim the suitcase was broken upon receipt, but it wasn't. The airport staff documented the issue, and later I was informed it was received as damaged. If it was damaged upon receipt, it would be noted at the destination airport, which didn't happen because a report was made. THY is making excuses to avoid refunding the cost of my suitcase. I request the necessary action to be taken.