Income tax compliance

My mother had a income of about 1lakh (from Fixed Deposit interest) for the FY 2016-17 and no other income. We did not file any return. Now we've receieved a compliance notification for the same year. As per the instructions on the email, I opened the Compliance Portal and selected ITR has not been filed and Not liable to file return of income; and submitted a remark stating the total income amount as shown in Form26AS. But even after submiting the response, Status is showing as Pending. There is also a Verification Issue List listing Other Source Income (NOS01) and Investment (NIN03), am I supposed to submit response to these as well? Could anybody suggest the best course of action.