This document is a guide detailing the Telecom Tax Audit service offered by Tangoe Advisory Services. It outlines the process of identifying, recovering, and suppressing erroneous telecom taxes, fees, surcharges, and regulatory charges on enterprise invoices. The service operates on a contingency basis, meaning there are no upfront costs and minimal client involvement is required. The guide explains that the typical return from the audit averages between 5% to 15% of the audited telecom tax spend. It also emphasizes the importance of validating charges by service type, jurisdiction, and carrier methodology. The document describes the steps involved in the audit process, including access to billing data, line-by-line analysis, quantification of prospective savings, and execution of disputes with carriers and taxing authorities. The guide highlights the rapid turnaround time for initial assessments and the ongoing validation of corrected charges throughout the engagement.