Sb deposits exceeding 10 lakhs

Hello Everyone, Please Guide me on this matter, My Mother, Being a Post Office Agent is Authorised to Open A/c's, Collect Monies from Public and deposit the same in Post Office. Sometimes, Due to Personal Work, Holidays, Technical Problem and other Official problem, she can't Deposit the money received from public in post office next day and deposits the same after few days, Till than money retains to us ( For which She is authorised in her Agency Agreement). But, as we live in a small house, to keep safe the monies received from public, My mother deposits the same in her Bank a/c and than withdrawl and deposit it in Post office within few days and Receives the receipt of deposits from post office . Now, we have received a letter from IT dpt. Asking about the source of the transactions because the sum deposited in saving a/c exceeds rs. 10 lakh. Is there any problem If we Reply to IT Dpt. explaining the whole process of all the transactions. * (Due to this process, withdrawls and Deposits in my mother's SB A/c are approximately equal. Thanks in Advance