On Google Play, I ordered an app with my Discover Gift Card, and I refunded it within 15 minutes. According to my Card balance, I have not been refunded yet. How will I know when I will get refunded?
Did you get an email from Google Play that a refund was made? If yes, you should be all right.
Sometimes, it takes time before refunds (or anything) shows up on PayPal or your credit card statement. Try again in a few days.