You have to change complete back panal and for the exact cost you have to contact Service Center.
If this solved/helped with your query "Accept as solution" will be appreciated.
back panel is just a piece of plastic so they can easily remove it...
Dear Samsung Member,
Greetings from Samsung Customer Support!
We request you to kindly visit the service center for physical inspection of your device. You can locate your nearest service center with this given link: https://www.samsung.com/in/support/service-center/
Thank you for writing to Samsung.
Samsung Customer Support