What should I do if I submitted an article to a predatory journal?
If the paper has not yet been accepted for publication, you are free to withdraw the paper from consideration. Depending on the policies of the journal to which you submit the article, you may need to disclose the prior submission, and explain why you withdrew the publication from consideration.

Unfortunately, there's little you can do to stop the publishers of the first journal from doing something unsavory with your article. You will need to exercise vigilance in monitoring the work in this area to ensure that the paper isn't mishandled or worse. Be sure to maintain records of all of the correspondence you have had with the journal—and make sure of all it is documentable—phone calls won't suffice here.

However, if all the journal has is a PDF of your original article, it makes it a lot harder to do anything with it: it is tedious work to convert it into the template that most publishers use without significant effort. Thus, without the original graphics and text files, it will be difficult for them to "transmit" the paper elsewhere.