Income tax demand notice

I am in receipt of Income Tax demand notice towards payment of tax Rs.27,340/- towards short payment of tax for AY 2011-12 under Sec.143(1)(a). 

I worked in a Company during April’10 to July’10 and another Branch of the same company during Aug’10 to Mar’11.

However tax deducted during Aug’10 to Mar’11 was not reckoned while filing return by that Company and entire TDS deposited during that period has not appeared in Form 26AS of AY 2011-12 but appeared in Form 16 i.e. mismatch in Form 26AS vs. Form 16.

As against the total tax payable by me for AY 2011-12 of Rs.32,321/-, total TDS deducted (and deposited) was Rs.35,018/- and refund amount was Rs.2,697/-.  But now I am asked to pay Rs.27,340/-.

Now I am in different Company. When I approached my previous employer for filing revised return so that correct tax amount appears in Form 26AS. They admitted that the mistake was due to wrong PAN number given against my name. However since it was done in earlier period, the present Manager is refusing to sign Form 27 for uploading and filing revised return.

Further I have not filed my current IT return i.e. for AY 2018-19 as refund of around Rs.40,000 is due for this year. If I file my return then the demand amount will be adjusted against the refund ( same thing happened last year, out of demand of Rs.27,340, my refund got adjusted on filing IT return for AY 2017-18 and net demand amount now is Rs.26,020).

For the demand notice, twice I submitted my reponse in portal as “Disagreed with Demand”. But still appearing in portal.

Pl clarify as to how to take up this issue. How can I cancel the Demand amount? When can I file current IT return?

Thanks and Regards

Srinivasan