I only emailed CS once, and heard nothing.
So I stopped by one of the local GameStops, showed my order (which was made online), and the clerk printed up two back-up codes for me. I haven’t tried them yet, but they have different SKUs, even though they are both listed on the receipt as “Forza Horizon 3 Hellca”. Will report later.
Still not sure who to talk to about the Mercedes.
Hello and thanks for your message.
As i said earlier, I dont have a gamestop local store nearby so i can’t go and show them…
I don’t know what to do…
Maybe if a community manager of Turn 10 or someone like that is looking at this topic… well, would he kindly help me ?
I can provide everything required about the order, i don’t know who i can contact now.
It’s so frustrating to support & pre-order games and to be denied what you bought, $100 is a lot of money…
You do know all the preorder cars are available already in the game…they just dont have the preset tune and you need to use credits to buy them
Not worth it to get so upset over it
I know it must be pretty disappointing that gamestop has let you down with this
Just enjoy the rest of the game
Shouldnt be spoiled by a couple of missing cars
Thanks for your message.
I know they are available in the game, but, as a tier 10 player, you surely understand the pleasure you have when launching the game for the first time and being delivered tier rewards, bonus items & all that stuff, it is a really good feeling and that surely is one of the main reason i pre order stuff 
Anyway, if by any chance Gamestop send me the pre order bonus codes after i already launched the game for the first time, will i still be able to redeem them and get the 3 free cars ?
Thank you.
Yes…you can redeem the codes anytime to get the cars…
Same as the warthog