I am a PhD student in electrical engineering, and I recently found out a published paper from another research group which I am collaborating through a joint project using exactly my idea and the data that I collected.
I don't have any public evidence that I was working on it, but since it is a joint project, the other research group was aware of my research and my ideas.
On their paper, they don't mention my work, they don't acknowledge and they didn't ask permission to use the data that I collected. They had access to my data because I needed to use their equipment to collect the data.
The paper that they published won the best overall paper of the conference and they got a prize of €2000.
I contacted the head of the research group to make them withdraw their paper, but they don't agree, they claim they are doing something different, but they suggested to add myself as one of the authors (even after the paper was published), which I don't agree at all since I didn't work on this paper.
I have evidences through emails, meetings and presentations that they were aware of my research. I would like advice on how to proceed.