Is the husband entitled to a full refund of the dowry if the wife refuses to be intimate with him, claiming sorcery, and consummation has not occurred, despite a valid seclusion having taken place?

Once the marriage contract is concluded, the woman becomes a wife, and she is obligated to obey her husband in what he commands her, especially regarding intimacy. If she refuses without a valid excuse, she is disobedient. If she has an excuse that prevents her from fulfilling your desire, then she is excused, and you can resort to lawful methods to resolve the magic if that is the cause. If the problem is not resolved, there is no harm in divorcing her. She must observe the 'iddah (waiting period) and is entitled to the full mahr (dowry) due to the occurrence of valid seclusion (al-khalwa ash-shar'iyya), which is considered equivalent to consummation. You can refrain from divorcing her until she compensates you if the request for divorce or refusal came from her side without any harm from you.