Howdy @IsabellaAvery01!
I'm sorry to hear that you're having issues with your payment method!
In these situations, we often suggest removing and re-adding your payment method from your Billing Information as a good first step. You can do some from here: https://accounts.secondlife.com/billing_information/
We've seen success with this in similar situations. If that doesn't work however, we are always happy to review the situation with you in a support ticket.
You can submit a support ticket here: https://lindenlab.freshdesk.com/support/tickets/new.
I went ahead and created a ticket for you this time! I'm going to be messaging you in world shortly with your ticket number, but you should also receive an email with the ticket number as well!