Let me explain to you , any dosha that is there in your horoscope does not get cancelled, no matter what you do. If somebody is born with a Scar on his / her body. Does it ever get cancelled. No he / she lives with that till the end. Similarly if there is any Dosha or planetary positions that we inherit from our past karmas. They do not get cancelled ever, we can only cover them through remedies, mantras etc. Sometimes they get covered completely and something we still feel their effect.
I can assure you , you do the mantra which I have given and it will help you tremendously.