Deep scratch on just unboxed IPhone12

I purchased an iPhone12 from an Apple reseller (Imagine) yesterday. The phone was unboxed and profile uploaded from an older iPhone. After this, while checking the phone, I realised some strange looking patch on top-right corner of the screen. A gentle rub with the finger revealed a deep scratch almost 12-13 mm in length. This scratch looks to be machine made, with the machine loosing track during assembly.

The Reseller refuses to help replace the phone.

what options do I have? I do not want to accept a sub-standard product from a brand like Apple. The customer centre says it is Reseller's responsibility and the reseller says it is unable to help. What should I do as an Apple customer of last 10 years? This is the first time I have faced quality issues with Apple.