25 August 2013
Write a letter in response to demand notice received clearly stating the facts and also request for correction of assessment year in challan enclosing a copy of the said challan.
26 August 2013
Look power for correction in Assessment Year mentioned in challan lies in the hands of AO. So only way out is making a reply to in response to notice received. If notice received from CPC then write to CPC with a CC to your Jurisdictional AO.