Hello, I sold an item with shipping planned via Mondial Relay, the buyer is requesting shipping by Colissimo. Before I modify the invoice based on the shipping costs, the buyer has paid. How can the buyer, who is okay with it, pay the difference? Thanks for your reply

Hello He can make up the difference by a method that works for both of you (paypal, bank transfer, cheque...) or you cancel the transaction and do it again with the correct fees.