How can I switch between the linked cards?

You can decide which card you want to pay with directly from the “Wallet” Tab. To select a card, tap on the switch arrow located under the payment QR code and tap on the card you wish to use for your purchase. This will update the card displayed on your payment screen. You can also switch cards when your phone is offline.

Please note that the card which appears on the payment screen is the one which will be charged.