(also on Netflix)
No, there wasn't even a 4th season. The series was discontinued, there were only 2 bonus episodes left to end the series properly.
But they still released a fourth season. It's even on Netflix
No, they only split season 3 into 3 and 3B. But that's all 1 season.
That was part 2 of season three. That came with a little distance. Then the series is over.
edit: Sorry, I was not shown the answer from Phoenix686. Now it's doubled twice. Can't delete my post, otherwise I would have done it now.
Double is better. ^^