HELLO
As se en on old Replays you say game works.. As se en on picture it wont, this is tried on diffrent countries... Same problem, how to fix or money back.. 
Viewing post in Ball Blitz Racing - TikTok Live Game comments
Hello!
I just tested and checked out, everything seems fine.
From the screenshot you provided, it looks like you entered your username with "@". Make sure you enter your TikTok username without the "@" symbol, as explained in the game and in the "Help Guide & Tips" document provided. This specific message isn’t 100% accurate (it’s a known bug with TikTok servers that I’m trying to resolve).
If you have any further questions or need additional assistance, feel free to contact me directly at livegameyouplay@gmail.com.