I am not sure if it's accidental or not as the fast charging is not working any more but normal charging is working fine. Still do you have any idea how much they charge ?
What is your exact issue? Is is related to charging, then it could be an issue with your charger too. Be it an issue with the charger or the phone, you will get free repair, provided there is no liquid or accidental damage.
We request you to kindly visit the service center for a physical inspection of your device. You can locate your nearest service center with this given link: https://www.samsung.com/in/support/service-center/
