Question on notice u/s 142(1)

Sir Before Getting this Notice you must have Recd a Notice u/s 147 / 148. Check with your client if this Case pertains to your Client. & If its your Own case  or your Clents case whatever it is & if No such Notice u/s 147 / 148  is recd  for Reopening of the assessment, then Notice issued u/s 142 after Lapse of 12 Months from the Last date of the Month in which the Return is Filed will not have Validity. 

initially examine, whether that Notice is legally right, like Rachna Sanyal said. if the Notice is issued after expiry of 12 months (6 months) from the date of filing your return and the date stamped on your return copy by taxman... if the notice does not satisfy that limitation clause naturally the Notice is invalid per tax law 1961 IT Act.

once satisfied with that teat you seek other opinion on documents, after all whatever documents you relied on to file your returns of income need to be substantiated that is all! 

Problem is AOs are pressured to collect more taxes legitimately is the principle, certainly not illegitimately that one needs to understand.

there mighty be any other obvious reasons that need to be duly countered by assesses ! that way you will be a good citizen. Never encourage any kind of corruption is my view!