Hello! @Steven Duncan
Welcome to the LastPass Community.
We truly apologize for the problem with your account details; you should be able to change your payment information by going to your web vault.
Then go to account settings
General Tab
My account
You should be able to change the card on file
Please let me know if you are getting any problem.
Please let me know if you need additional help.
Greetings!
Verlaine | Customer Care