Income Tax Refund

Hello,

I had filed ITR for one of my clint using ITR4, and had opted for Sec. 115BAC, as per d calculation refund was around Rs.90000/- and actual refund received as per department is Rs.75000/-. The difference as per intimation 143(1) was that the department has considered taxation as per normal slab rate (without sec 115BAC). Now how to intimate them and get d actual refund. Please guide.

Thank you in advance...