Big Business lets you Warn or Prevent Save of Orders and Invoices upon Credit Hold.
Credit Hold can occur when the customer is over their limit or a group limit, has Credit Hold checked, or exceeds Credit Hold Days setting by having unpaid invoice past due.
In Customer Prefs, in the Order Prefs, choose a setting for Credit Verification, such as Warn and in Invoices Prefs choose Prevent Save if needed to block over limit invoicing.