Currently, access to a subaccount's Settings/Billing Subscriptions, Payments, and Wallet & Transactions tabs requires a Payment Method to be on file. I can see this is valid for a new account without any transactions, but if an existing account removes its credit card on file, it also prevents an agency from accessing this vital information. Furthermore, there is no API access to LC transaction data; the only access is via Settings/Billing/Wallet & Transactions.