Q: What happens if I don't pay the article fee to a predatory publisher?

This is an unfortunate but not uncommon scenario, especially among new researchers as yourself. So, worry not. :-)

In fact, you shouldn’t have too much to worry about provided you haven’t transferred the copyright to them. From the information you have provided, this doesn’t seem to be the case. But even if so, the situation can be salvaged. Also, you have hopefully not let them know that you have realized they are a predatory publisher. If so, their tactics are likely to intensify.

In a way, that answers your question. If you refuse to pay the article processing charges (APCs), regardless of the geographical differences, they will try various tactics to either make you pay or to harass you. These include threatening to inform your supervisor/university/institute, threatening to go ahead and publish the article, making coercive calls, sending harassing mails, and so on.

We typically advise the researchers here to do the following (apart from the points mentioned earlier): inform your senior(s)/supervisor(s) as needed and stand your ground. Sometimes, communication may come to an abrupt end from the journal’s side, in which case, you should send a final mail stating that if you don’t hear of a withdrawal confirmation by a certain date, you will consider it withdrawn.

For similar situations and our responses to them, you may go through the following queries:

• How do I deal with these coercive tactics by a predatory journal?
• What should I do if my paper got accepted but the editor doesn't respond to my queries?

And to protect yourself from predatory publishers in the future, you may go through these resources:

• 10 Point checklist to identify predatory publishers
• The scientific predator has evolved - here's how you can fight back

Hope that helps. All the best for a positive resolution!