I recently purchased 50 kreds through power-up rewards, I have been waiting patiently but haven’t received them yet.
I decided to request support on Kongregate’s side mainly because the order registered properly on Power-up Rewards’ side.
They operate on regular business hours, so you won’t get a reply until tomorrow at the earliest, though. But that’s the proper channel and if anyone can fix your issue, it’s them.
When you redeemed your 50 Kreds through PowerUp Rewards on poweruprewards.com, you should have been given a redemption code which you can use here: http://www.kongregate.com/redeem