How do I file a civil lawsuit vs. someone who ripped me off over the net & is refusing to owe up?

Question

I made a mutual agreement with someone over a series of internet messages and a phone call. The agreement was for me to purchase a particular item from him, I'll pay him over internet banking and he'll send it out to me.
I pay up, he claims to have sent it and obviously I never got hold of it. He produces evidence that he purchased an express post envelope, which doesn't mean he's posted it, and a bank statement showing that he withdrew a sum of money to purchase the item I was to purchase.
However, his evidence lacked the receipt of the purchase.. I mean, he could've used the money to do other things! And, I checked with Australia Post and the particular express post article never reached its sorting centre to be scanned.
He therefore clearly breached our contract by 1) not posting the item, 2) probably never had the item to start with, & 3) the contract clearly stated the item be posted on 24/01 yet he posted on 25/01.
What other evidence I need to win a civil lawsuit against him

Answer 1

Well, you have your proof of payment and your testimony that you didn't receive. If he purchases an Express Mail envelope, he should have a tracking number that would allow you to track the package at www.usps.com to see if there is even proof he ever gave it to the post office. Like any other overnight delivery services, the USPS does intake scans and delivery scans. Add it the messages confirming the mutual agreement and that should be all you need to prove your case.