How to Audit Your Telecom Bill, Line by Line

Every telecom audit ITG does starts the same way: we sit down with the last two months of invoices and go line by line. We've been doing this since 2001, and we can tell you with high confidence that the average mid-market business has 10-20% in recoverable overcharges sitting in plain sight on their invoice right now. You just have to know where to look.

This guide is a DIY version of our process. It won't replace a full professional audit, but it will find the obvious stuff — and in most cases that's a meaningful savings number on its own.

Before you start: gather what you need

• The last two months of carrier invoices (PDFs are fine — paper is easier)
• Your current contract with the carrier, if you have it
• A list of all your locations, circuits, and phone numbers
• Any recent letters or emails from the carrier about rate changes

Step 1: Check for billing errors and duplicates

Carrier billing systems are old, complicated, and prone to error. Look for:

• Duplicate charges — the same circuit or service billed twice on the same invoice
• Charges for services at addresses you no longer occupy — very common after office moves
• Per-line charges for phone numbers that aren't in use — dormant DIDs the business stopped using years ago
• Feature fees you don't recognize — voicemail, call forwarding, IVR, auto-attendant fees sometimes get added without authorization
• Universal Service Fund fees that seem too high — some carriers over-apply them; a quick math check can reveal an error

Billing errors alone typically account for 3-8% of the invoice in our audits. These are the easiest wins because carriers will usually correct them and issue credits as soon as you point them out.

Step 2: Compare against your contract

Pull your contract and cross-reference the contract rate against what you're actually being billed. This is where most overcharges live. Common findings:

• Your contract expired and you rolled to month-to-month rates — which are often 30-50% higher than your contract rate
• Promotional credits that ended and nobody told you — the carrier offered "$500 off for 12 months" and months 13+ quietly added the $500 back
• Annual rate escalators built into the contract that you forgot about
• The contract was signed for one service level (e.g., 100 Mbps) and you've been billed for a higher one

Step 3: Audit your inventory

This is where a surprising amount of money hides: circuits, phone lines, and services nobody uses anymore but the business keeps paying for. Walk through every line item and ask: "Does someone actually use this?"

• Former-employee direct lines that were never disconnected
• Fax lines nobody has used in 5 years
• Backup circuits at sites that closed
• Hunt groups, call queues, and IVR routing trees from an old phone system
• Long-distance plans for phone numbers that only dial extensions

In a recent ITG audit for a multi-site retailer, we found $1,400/month of abandoned fax lines and dormant DIDs on the invoice — services that had been billed for years after the business stopped using them.

Step 4: Check against market rates

This is the hardest part to do DIY because it requires knowing what competitive pricing actually looks like in 2026 — and the carriers don't publish that. But a couple of directional checks help:

• If you're paying more than $8-10 per Mbps on a dedicated internet circuit in a major metro, you're probably above market
• If your UCaaS seat pricing is above $25-30/user/month for a business-tier plan, you may have room to negotiate
• If your MPLS circuits are still priced the way they were in 2019, you're almost certainly overpaying — MPLS pricing has dropped significantly

Step 5: Document and dispute

Anything you find, document in a spreadsheet: the invoice line, the charge, why you're disputing it, and the credit you're asking for. Send it to your carrier account manager in writing. Ask for credits and corrections going forward and retroactive refunds. Many carriers will refund up to six months if you push.