@lushifii The game is supposed to be new, as in, devoid of any user-created content, when you move the Sims 4 user folder. The point is to test with none of that content present. If the game runs properly, the problem is something in that old user folder, as is true in your case; if it still didn't work, you'd know the problem lay elsewhere.
You can start moving the content from your old Sims 4 folder to the new one. If you have any mods or custom content, test those first, and if you run into problems, use the 50/50 method to sort through the files.
https://modthesims.info/wiki.php?title=Game_Help:Finding_Problem_Custom_Content#The_50.25_Method
Once you've done that, or start here if you don't use mods or cc, move over the contents of Tray, not the Tray folder itself but just the files inside, and test again. Then move anything else you'd like to keep; here's a description of everything in your user folder:
https://sims4.crinrict.com/eng/2014/09/user-files-explained/
Where the game has generated a new copy of a file, it's best to leave that in place rather than restoring your old one.
Leave your saves for last, after you've tested everything else. Here again, move the files themselves, not the folder they're in.
For the missing pack, please contact customer support again and explain that you don't see the content in your library even after this many hours. But no, this shouldn't have prevented Sims 4 from launching at all.