I have contributed significantly to the paper and I was not listed as co-author instead I am listed in acknowledgement section in the end saying that thanks to my preliminary studies. I had sent the data to my supervisor before I left the lab and I have all evidences of work reports and weekly meetings. They repeated my experiments with my optimized conditions and produced their results in the manuscript and included few new data. I could not find much difference between my results and results obtained from their repeated work.
I am really disappointed with whole situation which I feel went against ethic science for a significant contributor to be dropped from the list of authors. There was no response to my e-mails from corresponding author that I asked for justification. Please suggest me accordingly, what can I do further, the manuscript is already in ASAP.