Will IndyLend ruin my CIBIL/Credit Score?

Only if they are a regulated bank partner. Most unregistered apps cannot directly update your CIBIL score.

• The Mechanism: To report to CIBIL, a lender must have a specific agreement with the credit bureau. It is expensive and regulated.
• The Scare Tactic: They will send you fake "Legal Notice" templates claiming they have reported you. They likely have not.
• However: If IndyLend is a front-end for a real NBFC (check your loan agreement's fine print), then yes, defaulting will hurt your score. Always read the sanction letter to see which bank is actually lending the money.