CEO & CTOHi Chris, this is a classic mistake that I've seen 3-4 times before. Had a good idea what it would be, so don't be embarassed, you aren't the first to do this.
When you open the dialog to buy parts or engines, you must click the engines tab to get engines. I can see from the history that you bought Parts each time you thought you were buying Engines.
I've given you some tokens back because I believe this was a genuine mistake.
