The order was paid. Why is it asking for more money?
Posted rule
Whalebuy's page on outstanding balances says a shortfall is raised when the seller's price turns out to differ from the one you submitted, and that the gap is mostly domestic delivery. The service standards add that a buyer sets a top-up against the real value when processing the order.
Read on Whalebuy's Shopping Agent orders have been paid for, why do I have to pay for outstanding balance? page, 21 and 22 October 2026.
In practice
Keep a little balance in the account during the buying stage. A ten-yuan shortfall can hold an order for a day if nobody is watching the notifications.
Misread as
The request looks like a surcharge invented by the agent. It is normally the seller's domestic postage, which was unknown when you pressed pay.