Sorry, but this is something customer support should be aware of. Besides, it shouldn't take him long to look up the answer.
If he was too busy responding to more important questions or concerns, he should have at least responded in a more respectful manner instead of just saying 'because' and ending the conversation.

I don’t want to be too harsh on them, since they are still new here, but this is not acceptable and shows a lack of professionalism.