Sometimes it is necessary to receive a refund from BitPay for underpaid or overpaid invoices. When this happens, you get a refund of the payment exception minus necessary fees.
When you send a payment to a BitPay invoice, you send the amount necessary to cover the invoice price plus the standard BitPay Network Cost. The payment amount is reflected in the price your wallet fetches from the invoice when you scan to pay. Because the Network Cost has to be paid to bitcoin miners for BitPay to access your payment, it cannot be used again. This means it cannot be included in the refund you receive from BitPay.
You must also pay a miner fee for your payment to a BitPay invoice, like every blockchain transaction. BitPay does not receive the miner fee that your bitcoin wallet includes in the outgoing bitcoin transaction. This fee pays your cost of confirming a transaction on the Bitcoin network. (What are Bitcoin miner fees?)
If you use an exchange or other service to send bitcoin payments to BitPay, the service provider may also deduct a fee from your outgoing payment. BitPay does not receive the fees charged by these services.
Finally, if you receive a refund for an underpayment or overpayment via BitPay's refund processing flow, the miner fee required to issue the refund will be deducted from the amount BitPay returns to your wallet.
To ensure the payment you send is exactly the right amount, BitPay now requires payments be sent with a Payment Protocol enabled wallet. Here’s our guide for paying a BitPay invoice using Payment Protocol.