Unauthorized credit card transactions can drain your finances quickly, making prompt action crucial. The first step is to block your card through your bank’s mobile app or customer service. This action prevents further misuse and should be followed by reporting the fraudulent transaction. According to the Reserve Bank of India (RBI) guidelines, if you report the fraud within three days, you may have zero liability. However, reporting delays can lead to limited liability or full responsibility if negligence is proven. To formally dispute a transaction, complete the necessary forms and provide transaction details. Banks typically take 30 to 90 days to investigate, during which the disputed amount may be temporarily reversed. Additionally, monitor your account for any further suspicious activity and consider filing a police complaint for larger fraud cases. Preventive measures, such as setting low transaction limits and using virtual cards, can significantly reduce the risk of future fraud incidents.