Should cash deposit in bank in fy 13-14 and no return file

Hi,

I am a salaried employee in FY 13 - 14 and  I had deposited around 3 lac rupees in cash in bank account which is in the name of mine as first holder, my father as a second holder, and my grandmother as a third joint holder. This cash deposit consits of Rs. 10000 deposited in each month from my salaried income which is 225000 gross and there was one high value cash deposit of Rs 175000 which relates to the cash deposit by my grandmother which she got from selling his jewellery and other accumulated savings. Out of which she invest this cash of Rs 125000 in Mutual fund in her name and gifted me the cash of Rs 50000 which i invested in mutual fund in my name through the same account. I had not filed the income tax return for that year under impression that salaried employee below 5 lac are exempted frm filing return and now i  got the tax notice regarding non filing in feb this year in which i replied the notice that no taxable income hence return not filed as my salaried gross was above tax slab but my net salary was below taxable limit but then i realised that i was wrong in not filing return.

Since my response to the compliance notice there is no communication from tax department and the status of the notice is showing as submitted.

I am worried now whether if income tax send me notice under section 142 (1) for my response and found such deposit in bank account. The amount of Rs 175000 belongs to my grandma but how can i proof this as i dont have the sales bill also please advise what action i need to take or I m too late for this and also advise whether income tax can scrutinse me in such case where i  had replied the notice saying no taxable income since my salaried income is below tax limit.

Thanks