The reason I set my buy price at $315 is I didn't want to buy until bitcoin was in a confirmed uptrend.
The igot help page says a future buy ordered won't be triggered until the market price (which they display on their home page) reaches your trigger price. The market price was $15 below my trigger price!
If Igot works like other exchanges, the market price is usually the price of the latest trade. But exchanges will still let you place sell orders for more than that, basically attempting to do the same thing you were, but with a sale. On Bitstamp right now for instance, there are sell orders from $278 to $306.
It's possible Igot does not work like an exchange though and they just took the opportunity to shaft you. Other than taking a quick look at the site, I'm not familiar with their service.