Rectification of demand but period lapsed

AMIT (bus) (444 Points)

30 September 2015  

AY 2010-11 Demand Raised of Rs.1500/- Due to Tax Credit Mismatch as the same is NOT appearing in 26AS but I have taken the credit on the basis of TDS certificates.

Now as the Rectification Period expired on 31/03/2015.

Please Guide me How to Rectify the Demand in this case, Whom to Approach for this ?