Tax dept not giving refund for tds

My mother has bank account with PSU bank. The bank deducted TDS and my mother filed for refund because she does not have taxable income.

The refund was refused because the bank had not deposited TDS with correct details. My mother asked the bank to correct the TDS details and the bank did so. The TDS is now showing in 26AS.

My mother again asked for refund for the IT dept, but the refund was again refused. The IT department gave the same reply this time too -  that there was no TDS deposited in my mother's account. This is not true. I downloaded 26AS form from the tax site and it is clearly showing that the TDS has been deposited.

How can my mother get a refund now? I don't know what to do. :-(.