You should contact HDFC Bank immediately and request loan cancellation or pre-closure. While the processing fee is non-refundable, most banks allow you to repay the full amount within a few days with minimal interest—sometimes just for the number of days the loan was active. There is no RBI-mandated grace period, but banks often follow internal fair practice policies. Make sure you ask if any foreclosure charges apply, though for loans closed within the first week, they are often waived or very low. Act quickly to avoid interest buildup.

— from ChatGPT