Apple Watch Replacement Difficulty

I've been having issues with the Apple Watch I bought from Teknosa since the day I got it. I tried to get help multiple times, but the problem still wasn't fixed. So, I decided to take it up with the Arbitration Committee. After looking at it, we found out that the watch needs to be replaced. When I told Teknosa about my decision, they told me that since the model is no longer being made or sold, they can only give me a refund and cannot do an exchange. I don't get why I can't get a similar replacement if the watch is currently sold out or not being made. When I tried to get the same model, they asked me to pay an extra amount of money, which could be anywhere from 5,000 TL to 6,000 TL. What will happen to the interest on the money I've been spending for a long time? How can I buy a watch with the money I have in this high-inflation situation? I want to exchange my item for the model that is currently in stock and closest to it. I really hope Apple and Teknosa can sort out this problem. This is not fair; sadly, I don't trust Apple and Teknosa anymore. If a fancy brand like Apple can't give you the watch, why can't they give you a similar model instead? Why is this happening? Are you causing financial problems for people in advance? I need my watch replaced with the right model as soon as possible and my issue resolved.