My code is published as original work by a different group. What should I do? I've found some code that I've posted online that has a BSD license published in a supplementary material of a different group in a high impact journal. The authors have replaced the name on the license with one of the co-author's names and added a header on my code. They weren't too careful and didn't delete my name and email some lines below that header.  I've contacted the corresponding author that promised me that he'll contact the publisher to correct it and nothing has happened in the past 3 months or so.
What would you do?
EDIT - Update.... It took 6 months from the moment I contacted the authors, and 3 months after I contacted the publisher to issue a Correction\Corrigendum that gave me credit for my code.*
This seems to be a clear case of plagiarism, and potentially a copyright violation.

The BSD license contains a line "Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer". If that was included in your Original code, then it seems that this was breached by the article authors.

But even in the case that this line was not included, then it seems to be still a case of plagiarism, as they are passing your work as theirs.

Contact the editor (or editorial office) of the journal. Provide them with a description of what happened (basically as you described in your question).
Also provide links to your originally online published source code. If you can, add proof of when you published it there (e.g. log files).

It would not hurt to also keep a copy of their present version of the source code they published, just in case it 'vanishes' from the internet and you want to show (e.g. to the editor/publisher) how they plagiarized you.