How can a third party debt collection agency have an account garnished without a judgement rendered by court order?

First its not a good idea to piggyback your question on another thread. This can lead to confusion. So I've moved your question to its own thread.

What makes you think that happened? To process a garnishment requires a court order.

Some exceptions to a judgement can be student loans, also in some paper work from places like pay day loans, people often sign to allow the judgement without a hearing.

Can you give us some details