The Guru placed you in the practice of service (Sewa) to rid you of your arrogance as it is the only medicine to treat this disease. However, when you relate Sewa (service) with a sense of pride achievement, and a demonstration of your potential, then the result is that sewa also becomes a mere expression of gross work. Those services are supposed to eradicate one's ego, but instead, it is used as fuel for your ego. You complain that you are unable to concentrate in meditation and that your mind remains fickle, but did not your Guru explain to you what sadhana (meditation based on Brahm Gyan) means?
Sadhna is not about increasing the hours in a sitting posture. It is about purifying your thoughts, speech, conduct, and intentions. Though you dedicated several hours, but in that pride, you overlooked that task of purification, and because of that, you went on to hurt several people with your speech and conduct. Now, when your seat of meditation is drenched with their tears, how will you be able to concentrate?
The Guru teaches how to walk with others and co-exist with peace and tolerance. Instead, you chose to see the flaws in others while turning a blind eye to your own. How then will you be able to meditate in the true sense? The Guru's principles and directions are not for talking and propagating alone. They are meant to be imbibed, internalized, and practiced with each breath you take. One cannot become a manifestation of the Guru by talking. For that, one has to uproot oneself (annihilation of the ego) and imbibe the principles enunciated by the Guru. Have you done that?
Please ask yourself whether these vices malign your path too. These vices push us away from the Guru. No matter how much we may glow externally, there can be no peace and contentment when the mind remains covered in malice. The ultimate grace of the Guru cannot be attained unless the mind is free from malice and dark instincts.