You where suppose to enter it on the ps4 itself that's what I did and I have the day and night dlc. I pre ordered my game on Amazon and that's what it told me when it sent me to dlc code it said redeem it on psn. That other code was for another code to be in the game if you pre ordered the game. I believe they said every one gets that code for pre ordering so I assume it will be in box since I did not get that one in a email lol
Edit dude go on psn and try to redeem the code there. I was looking at the site you said you entered the code there and that's for 19 characters so the code would not even be able to be redeemed there lol. Your code is still good just go on psn go on the store on your account and go down to enter a code or something like that then redeem the code 
