I'm a developer and if you didn't have a contract in place it's your fault.
Always enter binding contracts and both parties should agree to the terms prior.
Development and design work is not like most services. If you do not like what the developer or designer produced it's not their fault.
They already put forth the hours (their time is valued). Looks like this guy was sketchy but it's your fault if you don't have a contract or terms.
It sounds to me like you had a disagreement and mis-communication. I suggest you try to work it out with him.
I suggest you don't do anything with his personal details. If you leak sensitive information he could take legal action.
I read the other thread and it seems like he's not returning the payment upfront. Most freelancers don't do this and if you had a contract it would have been defined there.
Most initial deposits are not refundable.
I suggest you watch this video -
http://vimeo.com/22053820 - I have almost all of my clients watch it prior to entering a contract with them.