An underpayment sends less than the quote; an overpayment sends more. Coinvay’s described verifier expects an exact token quantity for a payment match. A transfer can therefore be genuine while the invoice remains unpaid because its received amount differs from the request.
Understand why the exact quantity matters
A checkout can add a small precision adjustment to help distinguish payments reaching the same merchant address. Removing those decimals can defeat matching. The buyer should copy the displayed token amount rather than use the invoice’s rounded dollar number as the transfer quantity.
For example, a quote might request 20.000417 USDC. Sending 20 USDC is an underpayment, even if the buyer intended to pay a 20-dollar order. Sending 21 USDC is not automatically better evidence: it is a different amount requiring a separate support decision.
Look for common causes
Exchange withdrawal charges, wallet Send Max behavior and manual rounding can all change the recipient amount. Native-coin transfers need a fee reserve in addition to the payment value; token transfers generally need the network’s gas asset.
Ask the customer for the actual chain reference and inspect the receiving amount. Do not infer it from the amount removed from the customer’s platform balance. A withdrawal service may show a gross debit that includes charges while sending a smaller quantity to the merchant.
Resolve the exception without inventing a success
Do not assume a partial payment can be topped up by a second transfer under the current exact-transfer verifier. Two independent transfers are not automatically combined into one quoted receipt. Similarly, an excess amount does not authorize the gateway to issue a refund from the merchant’s wallet.
Record the original invoice and all relevant hashes, agree on a resolution through the merchant’s support process and keep any return transfer separately identifiable. Avoid asking for another payment until staff understand the first receipt and the risk of duplicating funds.
Practical checklist
- Copy every quoted decimal and verify the net recipient quantity.
- Check withdrawal deductions before approving a transfer.
- Keep exception and refund decisions distinct from automated paid status.
Common questions
Will paying a little extra make the invoice complete faster?+
Not under an exact-amount matching rule. A larger transfer can require manual resolution instead of satisfying the quoted amount, and it does not accelerate confirmations.
Can I send the missing amount as another transaction?+
Ask the merchant before sending more. The current verifier does not promise automatic aggregation of separate partial transfers. An unsupported top-up can create another unmatched receipt.
Sources and further reading
Primary references and Coinvay product documentation. Check the linked pages for current details.
AI-assisted drafting, published by Coinvay. Examples are illustrative. Read our editorial approach.