Client appreciate my work but ask source file free of cost "This looks good! Can you please attach the source file? Then, we can complete the order. "
It sounds like they might not be aware that you don’t offer the source file free of cost. A message like, “I’m not seeing that you ordered the source file extra. Would you like to add it to this order?” could be enough to let them know that you’re not going to send it for free, without making them angry.