TDS wrongly deducted by the bank @ 20%

   A co-operative bank, of repute has wrongly deducted TDS @ 20% instead of 10%,( being cited PAN No. since day 1), on FD 's held by minor,  on poinrting out the mistake , now bank is discarding to file a revised TDS returns,(through its CA..who is willing to do so.. provided bank instructs them to do so..and ask excess TDS transferred from IT dept), and   Now bank is suggesting  Parent to claim refund of excess TDS from her  IT returns, thus shying away from its responsibilty to Do so.. what best action is avialable with the FD holder...as per as ITR filling and claiming of TDS. as in case of maturity of FD 's held with bank, she is likely to get less amount after redeemption , as excess amount of TDS has been deducted by the bank