Complex Black Magic spells can take time to remove completely
There are generally two actual types of black Magic in terms of severity or complexity. The first one being a “one time” process. This is when a Black Magic spell or curse is cast in order to cause pain, suffering, discomfort and even ill-health. This is a “one off” spell that can be treated by a professional spiritual healer. The healer or psychic will perform certain rituals, which in time will remove all the effects of the curse leaving the victim to recover and lead a very normal life. In general this is the most common of all Black Magic spells.
The more complex spell or curse is when someone is affected and then later re-infected with the spell. This is obviously being directed by someone who is determined to inflict the maximum of suffering by whatever means are possible. It is an ongoing process that leaves the victim weakened, fragile and could even prove fatal.
In this case the psychic would have to perform a whole series of rituals in order to cure the victim.
With such a powerful and continuous spell it obviously takes a lot more time for the rituals to work. The victim will need to consult with the psychic over several sessions in order to monitor progress and to allow the psychic to determine whether the spell is weakening or getting stronger. If the spell is difficult to remove then it becomes a personal battle between the evil Black Magic practitioner and the psychic who is trying to remove the curse. It becomes a battle of wits.