I buyer and sell on StubHub every once in a while but I just noticed my CC expired. How can I delete that CC and add a new one so when I am ready to buyer or sell, my account is up to date?
Not a problem at all!
You can add new default payment options in the 'Settings > Payment' section of the site located in 'My Hub'. Use the plus (+) link to add new ones and use the pencil to edit current ones.