Do you get this problem with Textbroker?

I've found Textbroker great for getting reasonable-quality articles written for not-too-high a price. I know you can't expect Nobel Prize-winning stuff for $5-$15, but I use those articles as a basis, to get some content up, and then flesh out the subject myself, gradually. Just saves some initial time for me, and the writers (in the 3-star and above bracket) have all been pretty decent, literate etc.

But I've run into some real hassle, here is what has happened:

1) I commission an article, I write quite clear instructions, in fact, I could have written half the article myself by the time I have written the instructions!
2) Writer (via a DirectOrder, a writer I have used before who is good) comes back with finished article which is fine, but she hasn't really followed my instructions, the article just doesn't really fit the title, it's got way too much fluff in it - 3 paragraphs of introduction and only 2 on the actual subject.
3) I ask for a revision.
4) Writer bails out - flags it as something like "Could not complete" (I forget now), thus preserving her 0% rejection rate.
5) I post the job again, making the instructions even clearer, to avoid the mistake the first writer made.
6) New writer does exactly the same thing! Mostly general fluff, with only a paragraph on the actual subject!
7) I ask for a revision again, though in somewhat peeved tone along the lines of "I thought my instructions were very clear".
8) Next thing - the article is "Available to authors" again, i.e. he/she has bailed too.

Just wondering how common this is? It hadn't happened to me up to now. It looks like I am going to have to write the *&^&* article myself.

I understand, these people aren't getting paid a huge amount, and it's not worth their while to rewrite an article which could potentially get refused again by us "difficult" clients. But I am surprised the system allows them to do that. Evidently the rate of pay is too low for many of them to even read the instructions properly!

It's worth bearing in mind when using Textbroker or similar services. As ever, you pay for what you get...

Maybe someone else has a similar experience, or maybe can even tell it from the author point of view.