Guarantee

To whom it may concern,

I have bought my iPhone 8 Plus in America last summer. The warranty of my phone hasn’t expired yet. I have a problem with my phone, I’m guessing it’s because of the main board (main card) of the phone. I live in Turkey and the authoritized service of apple in Turkey has told me that my phone hasn’t under warranty in Turkey. Is there any chance that you can help me with that problem?