Income Tax Department has received information about high value transactions relating to XXXXXXXX in FY 2018-19

A person has been receiving the following message continuously since the last few days from Income Tax Department through SMS:

“Dear XXXXXXXX - Income Tax Department has received information about high value transactions relating to XXXXXXXXXX in FY 2018-19. However, as per records available, ITR for AY 2019-20 has not been filed. Please file your ITR by 30.9.2020. You can view transaction details and submit online response under e-Campaign tab on Compliance Portal (https://compliance.insight.gov.in) - ITD”.

There are few lakhs of transactions done, which were actually based on a loan taken by his son. Further, there are certain stock market deposits and withdrawals and there are no ‘profits’ generated out of trades/holdings. There is no other income / property transactions of the person.

In such case, how to respond to the IT Department? And what happens if the person couldn’t submit the online response / ITR?