publications - Editor rejected my paper stating that reviewers had refused to review it long after submission; How can I understand what is wrong with my paper?

I am having very frustrated at the turn of events and review process. I had sent a paper to an International Journal. The paper was based on my work and well received by PhD committee of my Institute. The paper was submitted 3 years back. The paper was in status "Editor Assigned" for 6 months. After that its status changed to "Under Review". After 9 months in this status (15 months after submission date), I sent a polite mail to editor asking about how much time it will take to complete review? There was no response. After I month similar gentle mail was sent. There was no response. After month, I again sent query (18 months after submission). At that Editor replied saying that they could not review the paper as assigned reviewers either refuse to review or did not agree to review. The paper was rejected after 18 months without any review comment.

So how does one know where it requires improvement? If paper was not of required quality why they kept with them for so long?

I feel that it is wrongly rejected.

Is it correct answer?

How can it show status as Under Review and then Editor says no Reviewer did not accept or refuse. My understanding is that paper goes in "Under Review" state only after "Reviewer" accepts to review. So what would have happened? Why Editor requires 3 months just to tell the status and comes back with mail like this? Editor did not bother reply to mail. Is it that he got angry because of persistent queries.

I had even worst experience with next Journal. The paper was submitted and it remained in status "With Editor" for 9 months. Wiser by experience, I asked Editor about status? After persisting with it for about 2 more months, Chief Editor said that they rejected paper based on quick review as paper is not suitable to Journal as it does not meet its criteria like Originality, Depth etc. Again there no review comments about improvement.

It is not sour grape, I do feel that around 60% papers in that Journal do not possess these qualities and have been published in 6-8 months (after revision). If paper is not of required standard, they could have rejected in 2-3 months, why it took them such long time. If I would not have sent mail, probably it would have remained with them for long time. This work is now 3 years old not published anywhere and I even do not know what to do to improve. I am feeling very bad and really do not know what to do?

What would happened? Is it wrong to ask editors about status even after 9 months or year? Our University requires two Journal publication for PhD thesis submission and really do not what to do?

Many friends are suggesting that publish in Open Access Journals.