It is explained clearly in the twenty-first chapter of the Teachings of Lord Caitanya that the sound representation of Omkara is non-different than Krsna. Omkara is one of Krsna's innumerable incarnations and as such Omkara is completely transcendental. The impersonalist, however, has a tendency to place more emphasis on Omkara and less on the Personality of Godhead, Sri Krsna. Lord Caitanya appeared specifically to teach personal love of God through the chanting of the supreme Name of Krsna. For purification we need concern ourselves with no other teachings than those of Lord Caitanya; and what He taught was that in this age of Kali there is no other way to achieve God-realization than by chanting the Holy Names Hare Krsna Hare Krsna Krsna Krsna Hare Hare Hare Rama Hare Rama Rama Rama Hare Hare. Omkara is there, and one may chant Omkara and achieve impersonal realization. But we are Vaisnavas and we are seeking the supreme perfection. Therefore we are chanting the supreme Name—Krsna.
My dear Nandarani,
The answers are all right and you directly write him. Also invite him to question further if he does not understand. In this way go on and if there is difficulty consult me.
ACBS
P.S. Krsna has made all living entities perfect and therefore every living entity has independence. Misuse of independence is the cause of imperfection. Living entity being minute there is always a chance of misuse of his independence. This is unavoidable because that is the meaning of independence.