Once an author has signed a copyright transfer or approves publication of an article in a predatory journal, your chances of having the article removed from the journal are highly unlikely. This is why it is important to avoid predatory publishers from the start.
In the case that your articles is already published in a predatory journal, you can consider the following options:
What if your name is used without your permission?
Predatory publishers often include names of people within a field of study among the editors, board members, or reviewers for their journals without the knowledge or permission of these people. While you can take action and attempt to have your name removed from these lists and websites, many predatory publishers will simply not respond to your repeated requests. The following steps can be taken:
Who is on the Editorial Board?
Identify who is on the editorial board and check how qualified they are to review your work. Read profiles or look up board members on the Internet to review their credentials. In the case of a newer journal, you might consider contacting one of the members of the editorial board to ask questions about the peer review process.
Who are authors that have previously published in the journal?
Scan a few recent issues. Are all the authors from the same institution? Are there repeated authors or groups across a few issues, or one dominant author? If so, investigate further.
What university was the research affiliated with?
Check that the author is affiliated with an institution or university that is reputable. Does the institution have a program or expertise in the field that is being written about?
What is the acceptance procedure?
How long does it take for the journal to accept your paper for publication? Do they promise acceptance within a few days or weeks? A timeline that would not allow enough time for quality peer review is cause for more investigation.
What is the quality of the articles in the journal?
Read a few articles. Are they well-written, and/or provide data and a sound scientific method?
Was the publisher recently established or does it publish an unusually high number of journals? A recently-established publisher that produces 50+ journals requires further investigation.
What is the journal's publication history?
Does the journal have a regular publication schedule? Look for how many issues have been published each year, and for how many years.