Concatenate clientId + email for orders in a custom Module

I have an extension where by default assigns an email to the client and it never changes. This extension is to feed products to a few Marketplaces. This extension was working correctly, until a couple Marketplaces modify some email settings, so now it cant work by using the default email. So the solution to fix this is to concatenate the orderId + "ourdefaultemail" this will be exactly in the extension /../../order.php it should be a simple solution.