I submitted a paper to two journals, and the first published it, but I agreed to publish in the other; what can I do?

I submitted my research paper in journal X on 7th July, 2014. Journal sent me one thanks email immediately. After that I waited for one month for any response from editor but nothing came from editor side.

Than I submitted my paper in other journal Y. My paper was accepted in that Journal and sent for review from editor side.

At 30 August, 2014 I received one acceptance email from the editor or journal X that my paper has accepted and I was asked to submit publication fee of 90$. But I could not reply this email due to busy schedule and I was also not interested to publish my paper in journal X. After that I could not receive any email or revision or anything from this journal X.

I continued to work with journal Y, modify paper according to reviewer comments, sign copyright agreement and now paper is in publication phase.

Yesterday, by chance I open my Google scholar account and find paper that was published in journal X to whom I was not interested and who was demanding 90$. When I checked the online paper, I was astonished that the journal published my paper in its July issue and date of publication was 1st July, even I send this paper on 7th July and journal X notify me about acceptance and fee payment on 30th August.

How its happened that Journal X published my paper without my consent and published it in back dates. Now what I should do because the same paper is in final publication phase in journal Y to whom I have signed copyright agreement also. Please guide me tell me any forum to raise voice against that journal X. Because I send many emails to editor of journal X but receiving no reply from editor side. Any penalty or any other thing which I can do.