Did you enter the code from your receipt?

I ordered online and was not receiving a code either. But, an email did show up this morning and had been put in the spam folder because they used their old EBGames email address as the sender. Not sure why they did that, but you might want to check there.

I entered in my code and it said it was redeemed but he still shows as blank in the character menu, do i need to beat the game before he unlocks or something?

You still have to download him from the store. After that, close the game if you had it open, then going back in he should be there.

I had the same problem on XBox. Download Shao Kahn, start MK11, go to the time crystal shop, pick up Shao Kahn and press x, there should be written "you already purchase that kharacter" and then "install?" press x to install him. At least it works for me on XBox maybe it works also for PS4. Good luck.

I'm having the same issue but with the switch version, I had him playable but then as I closed the software and opened it up later he wasn't playable anymore and shows that I need to pay for him and not redownload

May be a silly question, but never hurts to ask. Are you always connected online when playing? If you're offline, a lot of content becomes unavailable. Anything you've unlocked (gear, skins, characters, stages), time towers, and the krypt are locked out if the game can't reach the servers. It pings rather frequently, so an unstable internet connection can cause issues.