Hi, hopefully I can help you out. Can you explain the issue you're facing in a little more detail? If you're accessing your wallet by double clicking the side button, you may want to try opening the Wallet app on your iPhone and seeing if that shows the “updating cards. Apple Pay will not work until cards have updated” message you had mentioned. If it does, and it doesn't load after a little while, try removing and re-adding the cards you have in your wallet.
To remove your cards, go to Settings > Wallet & Apple Pay > (Card Name) > Remove Card > Remove.
You can then add the cards back either through the Wallet app or through Settings. To add through Settings, go to Settings > Wallet & Apple Pay > Add Card. Then you can select the card type you'd like to add and enter its details. To add through the Wallet app, go to Wallet > Plus icon (+). Then select the card type you'd like to add and enter it's details. Based on the issues you were experiencing, I'd recommend not using the "Previous Cards" option as this could cause the problem again.
If the issue persists, contact Apple Support: https://support.apple.com
I hope you found this helpful!
-Dallen
