self assessment tax deposited

naresh kumar (director) (53 Points)

02 May 2018  
We have deposited 3140 at the filing of ITR in form no. 6 with self assessment tax Rs.3140 in month of March. In computation also shows self assessment tax paid with challan no. nd bank name nd tax payable nil.
we have received assessment order under sec 143(1) with Demand of rs.3140. Pls what we should do now to rectify dis demand.
thanks