The query lacks clarity as to what exact response was expected by NBFC and to whom. Every lender retains the option of enhancing interest from time to time as per contractual obligations. If there is breach of mutual obligations filing complaint against NBFC is the only option.
Dear sir, any NBFC is governed by Rules , regulations, Master circulars etc issued by RBI in this regard. If you are aggrieved by any such deceptive malpractices of NBFC, you can approach Ombudsman. Every NBFC need to adhere Fair Practises Code as stipulated by RBI in this regard.