TCS project release but not getting

I have asked for release from my project. Both manager and HR are not ready to give that. I have cited stress and technology issues. They are saying sorry we don't have confidence on you that you can perform on that technology since you haven't worked on that. Moreover I'm not doing work in my current technology as expected. They are saying that you're struggling to work on this project how can we assure that you'll work there effectively. Any suggestions what to do now. I need release. Should I stop doing work.