## TL;DR
Wrong-amount invoices are usually right-amount invoices the customer does not understand: proration from mid-cycle changes, a discount that expired, tax added at the end, or a plan change they forgot. Rebuild the invoice line by line with them: base, adjustments, tax, total. If the math checks out, explain it. If it does not, fix it and say what was wrong.

## The query

```text
invoice shows the wrong amount: support checklist
```

## Use this when

- Customers dispute invoice totals
- Billing QA and invoice audits
- Writing invoice help documentation
- "Overcharged" tickets

## Not for

- Accounting audits
- Tax advice
- Pricing design
- Revenue recognition

## Steps

### 1. Rebuild the invoice line by line

Base plan amount, proration adjustments, discounts, credits, tax, total. Do the arithmetic yourself before replying. Most disputes dissolve at this step for you, which tells you how to explain it.

Expected output: the invoice math verified or the error found.

### 2. Check proration from plan changes

Mid-cycle upgrades, downgrades, and seat changes create prorated lines that confuse everyone. "Why is this $137 instead of $99" is proration nine times out of ten. Show the date range each line covers.

Expected output: prorated lines explained with date ranges.

### 3. Check discounts, credits, and tax

Expired discounts (the 20 percent first-year deal ended), credits applied or not applied, and tax added on top. Tax especially: customers compare the subtotal to their plan price and miss the tax line.

Expected output: discount/credit/tax status confirmed.

### 4. Check currency and billing period

Charged in USD instead of EUR, or an annual charge mistaken for monthly. Confirm the currency and the period on the invoice match what the customer expects.

Expected output: currency and period confirmed.

### 5. Explain with the breakdown or fix the error

If the math is right: send the line-by-line breakdown in plain language. If it is wrong: correct it, reissue, and say what was wrong in one sentence. Never defend a wrong invoice.

Expected output: understanding or a corrected invoice.

## Template: the breakdown reply

```text
I went through your invoice line by line, [Name]. Here is the breakdown:

- [Plan], [period]: [amount]
- Proration ([change] on [date], covering [range]): [amount]
- Discount ([name], [status]): -[amount]
- Tax ([rate]): [amount]
- Total: [amount]

[If correct:] The total is right; the [proration/tax/discount change] is what moved it from what you expected.
[If wrong:] You are right, the [line] is wrong. I have corrected it and reissued the invoice. Sorry about that.
```

## Variant phrasings

### overcharged on invoice

Steps 1 through 3. Rebuild, proration, discounts and tax.

### invoice total does not match plan price

Steps 2 and 3. Proration or tax is the gap.

### wrong amount billed this month

Full checklist. Do the math before replying.

## Why it works

Invoice disputes are arithmetic plus missing context. Rebuilding the math gives you the answer before you write a word, and the line-by-line breakdown teaches the customer to read future invoices. Proration is the perennial culprit because it is legitimate, confusing, and different every month.

## Edge cases

- The customer was promised a price verbally: check the record. Verbal promises the system does not know about are a sales problem; honor or escalate.
- Multi-year deals with annual uplifts: the "wrong amount" is the contracted uplift. Show the contract line.
- Tax-exempt customers charged tax: fix and refund the tax. Keep the exemption certificate on file.
- The invoice is right but the budget owner is surprised: loop in the buyer. Do not re-litigate math with the wrong person.

## Provenance

Resolved from the public thread: https://vectle.com/posts/pst_0Ga8rChedc4ALuretUCFLA