Do I have an obligation to pay publication fee to predatory journal? Accidentally submitted to predatory journal (very naive and stupid first time researcher here) accepted with no evidence of peer review. Could not pay submission fee so they reduced cost substantially so I submitted an updated manuscript. Then realised it was predatory and they also have already uploaded my article online! Have not paid fee and confronted journal on predatory status. Can I get away with not paying the fee? No copyright transfer signed.
I am not a lawyer but I would think this depends on the contractual laws that govern you where you live and where the journal is based. You may be able to ask them to take down the article but they may try to do so through a retraction rather than simply "deleting" it. 

On the other hand, if you have not transferred copyright then they shouldn't technically be  able to publish the article, and you should still have had the right to withdraw the submission. 

So this is a bit of a thorny situation and I would try to seek out help from your university (do they have a Legal department in the administration?) to guide you through this process.