I submitted a paper in October 2018. After 2 months, the status changed to "awaiting CE decision" and stayed it ever since. I waited a month and sent an email to CE in February 2019. I did not receive any reply. I then waited another month and sent a second email to CE and editor assistant in March 2019, still no response . I don't know what to do next? Should I email publisher? Should I send another email to CE. Since the paper has been in the review process for 6 months, should I withdraw my submission? What if CE doesn't respond to my withdrawal, can I submit the paper to another journal?
Check if you are using the correct email address and try to verify that it is not outdated. You can also try emailing some other contacts to communicate your issue.
If you are not receiving any responses from the editor for extended periods of time, you are justified in withdrawing your paper. Just make sure that you clearly communicate your decision to withdraw, either through their online system or through email (or both).