I submitted my paper seven months ago and it is still under review. I sent several emails to the handling editor but I didn't get any response except every time I sent an email the status date was changed. So I decided to withdraw my paper from journal and I have written a letter to the editor-in-chief but he didn't reply except the status date was changed again! What should I do now?
One possibility to put this to an end would be to submit to another journal by an e-mail where you would explain the situation (the paper has been submitted elsewhere, you withdrew it when you realized it was not handled properly, and you got no acknowledgment of this withdrawal), and with a CC to the editor-in-chief of the first journal. That way, the editors of the new journal would know for certain that you withdrew before submitting again, and you would be covered from possible accusations by the first journal. However this corners the first journal in a difficult situation, so it might make them react violently; I would warn them before hand, and only use this as a last recourse.
You can also try to get advice and help from a senior in your field, who will know the editors and might help smooth things out.
A third possibility would be to contact a relevant committee in an academic society (EMS has an ethics committee that could be contacted about a publication in a math journal for example).
The handling editor is the wrong person to chase about this - if they want to withdraw your paper they can, of course, but if they are inactive (which would also explain why your paper is not getting reviewed) then chasing them doesn't do anything. Nobody else will notice, either. The best person to ask is the editorial office. The editorial office 1) works full time 2) sees all activity by all editors, thereby knowing who is active and who is not and 3) knows who to redirect your query to.
If the editorial office is inactive too I'd suggest writing something like "If I don't hear from you by X date, I will assume my paper is withdrawn". Then if X date comes and goes, you can just submit the paper somewhere else.