Who can rectify if tax Paid / tax Deducted not reflecting in 26AS Statement ?

To rectify these errors you may request the deductor:

to file a TDS/TCS statement if it has not been filed;
to rectify the PAN using a PAN correction statement in the TDS/TCS statement that has been already uploaded if it has made an error in the PAN quoted;
to furnish a correction statement if the deductor had filed a TDS/TCS statement and had inadvertently missed providing your details or you had not given your PAN to him before he filed the TDS/TCS return;
to furnish a correction statement if the deductor had filed a TDS/TCS statement which had mistake in the challan details;
to take up with the bank to rectify any mistake in the amount in the challan details uploaded by the bank.