Update credit card details

[Daibach2]

My credit card linked to my monthly payment is due to expire and I cannot find how to update it

[pgn]

As you posted in Pay As You Go, @Daibach2, assuming either PAYG Rolling Plan or you previously added a card to auto top-up.

Dial 4444 and register a new card there when prompted

Guide How to Top Up (PAYG) 

You may find it in your MyO2 App also

Don't miss the View All option to fully expand the page in the app.

Good luck!