Income tax demand

Dear Sir

I have received the rectification order dt.23/02/11 wherein the ITP have rejected the application for rectification.

I wish  to inform you that the  an amount of Rs.40000  has not been shown in the ITR deducted towards interest on housing loan

   So I called CPC at Bangalore and intimated about the same, replying my call i was asked to send the Form 16 and the housing financial institution statement, alongwith the rectification application.

Therefore I sent the same immediately

Now they have sent me again a demand order asking me to pay the amount immediately.

Kindly suggest what is to be done.