OnePlus India — Vertical Line on Display post upgrade Oneplus 8T

Address:

Mumbai

Dear Sir/Ma'am,

I am Raj Sanghvi, i am the very early buyer of Oneplus 8T and had bought the phone during its launch in October 2020.
But suddenly after new firmware upgrade there is 1 vertical green line which has started appearing on the display. On complaining it to customer care, i have been told the this issue have been been by many users and free replacement of display will be provided but here in Mumbai Service center is demanding charges amounting to 14300 for the same.
Please help..