There's not much else to add except that you didn't really get scammed as you didn't mention anything about a contract.
It's not because he answered "ASAP" that you shoud start working on it ASAP, without a contract. If he wants it ASAP then he needs to start a contract ASAP.
NEVER EVER EVER start work without a contract. Even if you are almost certain that they want to use your services... you don't know who else they are talking to or interviewing and they might find someone else they like better.
Did he actually ask for you to send him a sample or do the job or did you do it on your own accord?
If he didn't ask for "free work" then I don't see why you should report him since the fault isn't his.... you just jumped the gun here and assumed he would hire you. Big mistake.
Arturo, you made a mistake. Learn from the mistake and move on. It is important that you NOT think about that person who did not pay you. Don't try to communicate with him. Don't look for him. Don't think about that. You can't succeed unless you let that go and move forward.
YOU are the person who matters. Not him.
You could, in fact, flag the job, which you will find with the job post and give your reasons. Although Upwork cannot help you at all (because you did not find out how the system works before taking the job), they might take note of this so-called client, if he stays around.
Before you bid on any more jobs, please do yourself a favour and read everything there is to read about starting on Upwork (and all the links) in this thread:https://community.upwork.com/t5/New-to-Upwork/Getting-Started-on-Upwork/m-p/264214#M2460
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