Yeah since Allah is omnipotent...I don't think black magic or any such shamanism has the power to override Allah's decisions. If you are meant to go through pain, you will. Like poet said:
The Moving Finger writes; and, having writ, Moves on: nor all thy Piety nor Wit Shall lure it back to cancel half a Line, Nor all thy Tears wash out a Word of it.
I think instead of accepting this we find more comfort in believing that someone is out there to get us.
And Black Magic and Hasrat is Evil-something that may change your Taqdeer. Although Allah is the Most Powerful but this does exist...please watch the youtube video if possible. Allah has given individuals power to test them and test those who are affected by it.
Magic can also be dispelled by the power of the Glorious Qur’an, which was sent down as a cure and mercy for believers; doing so is highly commendable. This is based on what is known in the Sunnah that angel Gabriel used the Qur’an (Al-Mu`awwidhatayn, or the Two Protective Surahs, i.e. Al-Falaq and An-Nas) in dispelling the evil charm done to the Prophet (peace and blessings be upon him) by the Jews. Moreover, surat Al-Baqarah is known to have the power of driving away evil spirits and dispelling magic.
Regarding Black magic and how to dispel it, the eminent Muslim scholar, Sheikh Muhammad Al-Hanooti, member of the North American Fiqh Council, states:
“The Qur'an talks about black magic in surat Al-Baqarah: “And they followed what the Shaitans chanted of sorcery in the reign of Sulaiman, and Sulaiman was not an unbeliever, but the Shaitans disbelieved, they taught men sorcery and that was sent down to the two angels at Babel, Harut and Marut, yet these two taught no man until they had said, "Surely we are only a trial, therefore do not be a disbeliever." Even then men learned from these two, magic by which they might cause a separation between a man and his wife; and they cannot hurt with it any one except with Allah’s permission, and they learned what harmed them and did not profit them, and certainly they know that he who bought it should have no share of good in the hereafter and evil was the price for which they sold their souls, had they but known this.” (Al-Baqarah: 102 )
Before we try coming up with statements in attempt to falsify Black Magic or a mishap due to such evil ..please be cautious not to deny the words of the Quran :)