I have been using some online proofreader tools for checking for grammar issues in my writing, but I have found that the solutions they give are not so good at all.
For that reason I would like to know any human-proofreader service that somebody could recommend me. Some of the characteristics of the service that I am requiring are:

* Not so expensive
* Confidentiality, I do not want my article to end up published by somebody else
* Reliable

Could anybody has experience with those services and could recommend me one? I need to review an article asap

Thanks