Does one who calls to guidance receive the same reward as those who follow him in giving charity until the Day of Resurrection, even if the one being called already knew the hadith but had forgotten it and only remembered it upon seeing the caller? And is it permissible for the one being called to renew his intention to follow the Prophet, peace and blessings be upon him, instead of the caller if the caller has harmed him?

The questioner should focus on her own destiny and deeds and hope for good for others, as that is a good deed. As for wishing to deprive someone of the reward of the Hereafter, that is from the impurity of hearts and must be rid of. No bad deed from another person justifies it. In general, a person who deserves a reward for guiding to good or calling to guidance cannot have this reward cut off by the one invited, for the matter is in the hand of Allah, who promised this reward.