You've to redeem your credits and then you get a mail from Tripoto if at all your credits have been redeemed. If by any chance they are out if coupons you have to wait till the next Time.
I did the same and within minutes received the e-mail asking to share the name, contact num, email id, address and the code. I have responded back to them with necessary details. Now lets see this gets delivered in how many days.