Interest on Refund Amount of income tax

can any body tell me,

as  a practical step

Income Tax deptt done the assessment of assessment year08-09 in a.y 8-9,

but ITO not sign the cheques and not despactch the cheque

but in assessment  year 10-11 deptt send some cheques by hand and not despatch, Deptt not give any interest on refund amount upto Assessment  year10-11.

what we will do .

if any body give the answer send my mail id :- sanju_ca47 @ rediffmail.com