Indiana law requires the Indiana Department of Revenue to list all retail merchants whose registered retail merchant certificates (RRMCs) have been revoked due to nonpayment or non-filings of delinquent sales and/or withholding tax online. An RRMC is the certification a retail business must have to operate lawfully in Indiana. Refer to Indiana Code 6-2.5-8-7a for more. Check to see if a business has a revoked certificate: