HELP ON REPAIRS ISSUE

I am Vinita Krishnan, and am writing to you as I am not getting desired support from Apple in relation to a service issue on my brand new Iphone 12.

Just a background, I purchased a brand new phone, Iphone 12 under proper bill and proper box.

1. I started facing issues on my phone and on 12 August 2021, I sent my phone to apple authorized service center. They have responded that there is an unauthorized modification causing internal damage on my brand new phone, and also in one of the emails mentioned it has been tampered. My warranty was rejected.
2. My phone was maintained in very good condition, and I have not shown/sent my phone to any unauthorized place and given the warranty which was available with my phone, the moment my phone started giving issues I called up apple support and as per the authorized service center shared by them, I sent my phone.
3. I am not getting desired support from Apple support/Apple service center/Apple repair center. I am NOT satisfied with the job sheet shared by repair center and service center - All it says iPhone 12 (which is brand new phone) - unauthorized modification and internal damage. I have requested multiple times/umpteen times to kindly let me know details of the same so that I can understand the problem and take actions accordingly, unfortunately I am only stonewalled.
4. Therefore, I had reached out to apple privacy team. While case notes have been shared with me, the case notes (basically conversation between me and apple support team) is not giving me any additional data/information. Basically, my ask was to get details about what was the unauthorized modification that has been detected on my phone because of which my warranty has been rejected.

Would be grateful if you can look into this and share the details of the issues diagnosed on my brand new phone so that I can take actions accordingly.