I got the same problem

You can buy cd keys here

https://www.gamivo.com/search/Company%20of%20heroes%20Night%20fighter

Info how to use your key code

Cost some time 

I fix it in 10 min got all the skins now

Head over to companyofheroes.com/ and select "Register". 

1. Register your free Relic account on the COH Development website.  Remember to verify your new Relic account by clicking the link you’ll receive in your inbox. 

2. Log into your Relic account on the COH Development website here and go to your Profile > Settings > Connections  

3. Connect your profile to Steam by following the on-page link.  

4. Go to your Profile on the COH Development website and select "Rewards" and "Code Activation" here.

5. Enter the offer code from the Amazon Prime Gaming site. 

6. Load up your copy of Company of Heroes 3 on PC. 

7. From the main game menu, click the notification bell icon at top right. There should be a notification message that prompts you to claim the reward in-game. 

8. Enjoy your new item! 

Don’t have Company of Heroes 3 on PC yet? Go to companyofheroes.com to pick up your copy!

Sorry mate didnt read your comment 

Maybe next month we will see more skins for wehr ??

I think they bring it out slowely 

Quess we have to wait 

Agree. Unfortunately i missed the Wehrmacht night fighter skins (with the Grenadiers). On prime gaming it says it ended on may 18 and now you cant get the code anymore.

I contacted sega. They told me there is no way to go back and get those skins once the code expires. It was frustrating to learn that.

i found one 

https://plati.market/itm/company-of-heroes-3-night-fighters-wehrmacht-bundle/3712419?lang=en-U 

place a S after the U  i cant paste a complete link

you need crypto or buy a giftcard with paypall seems the best way to buy something here 

I bought a gift card at digiseller.market, create an account, buy a gift card with a value of $1.60 (you can set it yourself) and then you get 2 codes that you can enter at platimarket if you choose gift card as a payment method. 

i missed only 2 skins and buy them both @ platimarket

you can find some skins on ebay to

It would be nice to have the night fighters skins al.

 it looks like now they are not going to come out @primegaming.

 The developers should pay a little more attention to Skins. 

Units from Batlle Groups now have no skin at all. But for HQ, you do have skins.

also The remaining skins of the Hammer and Shield DLC are also still unreleased.