Iphone 11 hardware problem

Hello, i have an iphone 11 black 128 GB which is still under warranty and has a hardware problem. It has been send to the local authorised seller who gave me the feedback about the hardware problem and has informed me that a new phone will be send to me in 2-3 weeks time. i would like to know if its possible to have an upgrade to iphone 12 with some concession done in payment as i will be without a proper phone for quite some time and it is causing me lots of inconvenience. i am an educator and the phone was my working tool specially when you have to keep in touch with your student.

Thank you