Income tax refund

I had filled an ITR of my sister which is a salary return. In the return, there was a Refund of Rs.14000. After that, i filled revised return showing no refund and no tax. Meanwhile, my sister received amount of Rs14000 as IT Refund in her Bank Account.

Its almost 4 months over and no Income Tax Demand of Rs.14000 received yet.

When its normally expected to receive demand in such case? Will they charge any Interest on the amount?