On July 14, 2015, the Department assessed the Taxpayer for gross receipts tax, penalty and interest for the tax periods from April 1, 2011 through December 31, 2011. On July 28, 2015, the Taxpayer filed a protest to the assessment. During the period in question, the Taxpayer did property inspections on an as-needed basis for a mortgage services company. The Taxpayer did not realize that she should be paying gross receipts taxes on the services she was providing. On March 13, 2015, the Department issued an audit notice to the Taxpayer and gave her a 60-day deadline, ending May 12, 2015, to obtain any necessary nontaxable transaction certificates (NTTCs). The Taxpayer contacted the company and asked for an NTTC. The company told the Taxpayer that they were being audited as well and could not issue any NTTCs at that time, but would do so when they could. The Taxpayer was not in possession of the NTTC by the deadline. In August 2015, the Taxpayer received a Type 2 NTTC from the company. The Taxpayer did not argue that she was engaged in the business of performing services and that these receipts would normally be subject to the gross receipts tax, but she did argue that she should be allowed to deduct her receipts. Pursuant to Section 7-9-43 NMSA 1978, any deduction claimed by a seller who is not in possession of the required NTTCs within sixty days from the time notice is given shall be disallowed. The Taxpayer was not in possession of the NTTC timely, and was not allowed by statute to deduct the related receipts. Interest is required to be paid on all taxes not paid on or before the date on which the tax is due, and a lack of knowledge about the requirement to pay taxes is considered negligent and subject to penalty, so interest and penalty were properly assessed. The Taxpayer’s protest was denied.