The way component refits work in VEGA Conflict is slightly different than in our other games. When you decide to refit a module, you are given a partial refund of whatever component you are replacing as soon as you begin the refit.
For example, if you replace Plasteel II with Tritanium II, you get a few resources back for the Plasteel II. That refund is then deducted from what you pay for the Tritanium II. If you remove a component and do not add another one, you can see what you're getting refunded for that component in the cost section of the refit screen.
As soon as you hit "Refit" that refund takes place. So if you decide to cancel the refit, even within the 5 minute grace period, your components will already have been removed and refunded, leaving an empty module or ship.