Previous postdoc supervisor removed my name in the published article In my previous postdoc, I had completed work with my supervisor. The idea was provided to me and I did all the mathematical derivation and generating all the results. We published two conference papers, one with me as the first author, and the second one in which he was the first author. We also submitted the work to a journal but it was rejected. Then, I moved out and took another academic job. I did not have time to work on the rejected journal paper and incorporate all his suggestions. Therefore, we stopped discussing it. Very recently I found that this paper is accepted in a journal paper, and he is the sole author of this paper.
The published paper is 80-90% the same as the rejected paper that was submitted to the journal, and 60% the same to the conference paper that he is the first author (in IEEE they allow the same work to be published in conference and journal). This is completely unethical, to remove my name from the article. In this case, can I complain against him to the editor of the journal, and IEEE? What action can they take, retraction?
It could be that your co-author attempted to reach out to you in order to get your permission to use your name but never got a response, i.e. old email/ not known address, ran out of time and had to publish without your name.
I would advise getting in touch with your colleague first in order to establish what happened before using the nuclear option.  It may be your colleague will assist in amending the published article.