My Shopify account is saying 'too many attempts to add a credit card'' and my bill payment is not being deducted, my store has closed and my business has shut down, can someone let me know how to resolve this as soon as possible?

customers have been complaining how they’re not able to place orders bec a page saying “there was a problem with our checkout” pops up, pls help so I can fix it ASAP,  losing customers