Trance,
Sorry for the confusion here. We use machine learning algorithms to prevent fraud and they're not always 100% accurate. If you feel you've had a transaction cancelled incorrectly send support an email. We regularly review transactions and push them through at the original purchase price upon request. I also wrote a bit about our fraud program in the fourth section here:
http://newsbtc.com/2013/11/07/coinbases-olaf-carlson-wee-answers-questions-users-technical-issues/Hope that helps!
I responded to Coin Base and they basically said "sorry you had a bad experience"
I basically mapped out the scam to them and sent it as a response showing my evidence.
Essentially COINBASE uses "Customers" 'cash/bank deposits' as loans to purchase BTC.
When BTC drop in value AFTER the order is placed, COINBASE goes ahead and executes the transaction and earn the small premium off of the listed price when the order(s) are issued. If BTC go up in value, COINBASE cancels the orders and pockets the amount GAINED from the inflated price that occurred during the "Wait Period" customers are required to wait for their coins to be deposited.
I purchased a few BTC at $220 per/BTC, the hour before the BTC were to be deposited, Five days later COINBASE cancelled my order, claiming that "the account appeared to be of fraudulent nature" which was entirely NOT TRUE. After doing some personal research of my own this happens to be a common occurrence amongst other COINBASE customers. Essentially, COINBASE uses customers bank accounts as their own 'Piggy Banks' to purchase BTC @ low prices and sell them at higher prices...Enough said.