Source: EU WoT Support
Some of you may experience issue where Twitch Prime package is not added to the account.
If you have not received the goods, make sure that your Twitch Prime account is bound to your account you re currently playing.
If the issue still persists, go to your account management page and unbound the Twitch account, after this bound it again and play a battle, goods and missions should be added to the account.
Wargaming Support Team”