Filled itr for wrong ay mistakenly.

Hello Experts,

I have a query regarding ITR E-Filling. I am novice to the Income tax and it’s constitute. Actually I filled my ITR online myself but by mistake I filled salary details and TDS details of AY 2013-14 in the ITR form for AY 2012-13 and after I realized my mistake I again filled ITR for AY2013-14 with same details that I filled in ITR form for AY 2012-13.

But I wasn't able to revise or cancel my wrong ITR for AY 2012-13 and now it has processed and income tax department has demanded me the tax with DIN. But as I know the ITR filled was wrong so is there any way that I can ask income tax department to check my ITR for AY 2012-13 as in this year I didn’t have any income and rebate the tax demand?

My second query is that, as I am person with income only from salary so if from the above qerry I don't get the rebate on tax demand, then if I pay tax demand online then which type of Payment i have to select? Is it (400) Tax on regular Assessment?

Please help me on theses queries? I would really appreciate your help on this.

Thank you in Advance.