Am I obligated to maintain ties with my elder sister who has severed relations with me, our paternal uncles and aunts, and our maternal uncles and aunts, and refuses my visits, claiming she has no relatives, despite my repeated attempts to foster kinship with her?

The Prophet forbade turning away from each other and severing ties between Muslims, and this is even more obligatory among siblings. Maintaining kinship ties is obligatory, and severing them is forbidden. Maintaining kinship ties is not limited to visits; it also includes everything that is customarily considered a connection, such as giving money, fulfilling needs, visiting, and exchanging greetings through correspondence. If some relatives are harmful, then the connection should be maintained in a way that avoids their harm. One should strive to maintain ties with a sister through correspondence via social media, and there is good news for maintaining ties with her despite her cutting them off. For the one who continues to maintain ties with his relatives who cut him off, it is as if he is putting hot ashes in their faces, and he will always have a supporter from Allah.