'alr approved some time ago'

Not a kata issue, it's a problem with your code. Read this

Please, NASM Translation

The kata isn't broken, your code is wrong, check how you use switch.

Thank you @tbesmer!

Not a kata issue then.

I think when you run this check:
(n.substring(0,1) === "4" && n.length === 13 || n.length === 16)
It should really be:
(n.substring(0,1) === "4" && (n.length === 13 || n.length === 16))

What failures are you getting? I cannot see your solution so I've no way to know what it is happening unfortunately.

For my solution using 'C', random tests are failing.
The error message is not helpful either.
@treffynnon could you plese look into it. I don't want to forfeit :D

Test fails:
For example this shouldn't output "VISA":
4111111111111111
4111111111111
4012888888881881
41111111111111
411111111111111

But the definition says, it's VISA