A property investor in Mumbai was charged a significant late payment penalty by their builder, calculated daily using SBI MCLR + 2%. The investor questions the legality of using MCLR for such penalties and seeks advice on how to proceed. It's recommended to review the builder-investor agreement for any penalty clauses and consult a local lawyer for professional guidance. If the agreement is one-sided or the builder is unresponsive, pursuing action through the consumer forum may be an option.