Demand notice for fy11-12

Hi,

I received a demand notice for FY11-12 from IT dept. I have paid the amount as indicated via echallan.

How do i determine if the return has been processed ok and the matter has been closed? I did not receive any acknowledgement from CPC for the amount paid. Do I need to refile any updated return indicating payment of demanded amount?

Request you to please guide me in this process.

Thanks in advance.