Check whether the unclaimed TDS amount is reflected in income tax website, 26AS.
If so, As per sub clause (d) of subsection (1) of section 143 of the Income Tax Act 1961 'an intimation shall be prepared or generated and sent to the assessee specifying the sum determined to be payable by, or the amount of refund due to, the assessee under clause (c).
So in this case an intimation under section 143(1) will be sent to your address or to the registered mail id with the income tax department.Then you can file a rectification return as per section 154 of Income Tax Act 1961 after claiming the TDS amount, which is not claimed now. This is the only solution available to this problem.
Note that Income Tax dept will sent an intimation u/s 143(1) only if the TDS amount is reflected in their website, 26AS, because then only section 143(1)(c) will get attract.
In short wait for the Intimation, if TDS amount is reflected in 26AS, and do a rectification return after claiming TDS amount.