code: public BillingInfo getBillingInfo(final String accountCode) {
          return doGET(Account.ACCOUNT_RESOURCE + "/" + accountCode + BillingInfo.BILLING_INFO_RESOURCE,
                       BillingInfo.class);
      }
docs: Lookup an account's billing info
  <p>
  Returns only the account's current billing information.
  
  @param accountCode recurly account id
  @return the current billing info object associated with this account on success, null otherwise