Fingerprint calibration can be done by yourself or you can move to service center. For this you need an PC because you've to debug your device. So if you want then I can tell you the process which is going to be a long one. If you want then you can move to customer care and before moving to them you can take an appointment with Samsung members app.
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