Urgent: Trying to redeem new code but "invalid"

Hey, this is a bit of a last resort but I've been trying for a literal HOUR to redeem this code I just got from Amazon for the Sims 4 pack Get together. Before you ask! 
Yes I have cleared the cache 
Yes I deleted & reinstalled both sims & EA 
Yes I have gone through the EA Website instead of the app
Yes I have repaired the game
& YES I have contacted support who has no idea what they're doing &/or ran by bots. 

What happens is I put in the code, the game shows up the pack that the code is for & I click to continue now all of a sudden code invalid?