My research paper was stolen by the co-author and published as his own. What do I do? All the data the paper is based on is my own work. I got it accepted in another journal but now I cannot get it published according to the copyright terms and conditions.
The first thing would be to contact the editor of the journal that published your co-author's work, and to explain the problem to them. If the proofs that it is your own research are sufficient, they might consider the previously published paper as plagiarism, which should unblock your own publication. In this process, it might be worth contacting also the journal to which you submitted, so that they can confirm the date at which they received your submission.
Right now, I would say that the best move is to contact the two journals editors with the proofs, and see if they can sort things out. You can also consider in the mean time publishing your paper to an open repository (such as arXiv), if it does not interfere with the copyright policy of the journal you want to publish to.