Do they have stated the exact reasons for rejecting your submission? Usually, an accepted article would not be rejected by a journal after two, three months unless there is a strong reason to do so. I do not believe that there was a mistake between acceptance and rejection since both review reports were positive. I cannot imagine even a handful of reasons that could lead to reject an article after accepting it for publication. First, obtain a clarification from the editor if you have not received this so far. Perhaps, you can also go for the publisher or society/association to whom the journal belongs if the rejection reasons are not adequate. However, I am not sure how they could infulence the editor's final decision.

Muhammad Rahim , I agree with Manjula Wijewickrema . There is no logical reason for rejecting your paper after having accepted it twice. Maybe there was a mistake - the editor sent you an e-mail that was supposed to be sent to somebody else. Before you turn it into a fight, it would be better to send an e-mail to clarify the situation.

All of us make mistakes. Maybe this was the editor´s case.

In any case, the last letter of the editor should contain reasons for refusal. Before moving forward, it is necessary to clarify why there is a contradiction between the previous message (about the acceptance of the article) and the last one (about its rejection). This is only problem. In general, if they write something like: "We changed our mind", you will have no reason to demand publication. After all, the editors have the right to refuse your text, they are not obliged to publish you (by the way, they are not obliged to conduct a full analysis of your article too). I do not think that any reasons other than the content itself can play a role in its future fate. There is a saying in Russia: "You can't be cute by force" (Nasil'no mil ne budesh)..