API can't provide user ID

This is for kraken only, you don’t need to for helix

That is correct, except you omitted the username, so no results will be returned.

(well an error

{
"error": "Bad Request",
"status": 400,
"message": "Invalid login names, emails or IDs in request"
}

)

So I assume you have omitted the name from the call, so whom are you looking up?

Also when you say banned, I assume you mean “banned from a channel” and not “banned from Twitch”