Am I obligated to visit my family and check on them, despite the long distance (30 km) and their harming my husband and their cutting ties with me, and would I be sinful if I do not maintain ties with them since they have cut me off?

Maintaining kinship ties is one of the greatest obligations, and severing them is a major sin. The true maintainer of kinship ties is one who connects with those who have cut him off and is good to those who have wronged him. If your parents or one of them are among your kin, then maintaining ties with them is an emphasized obligation. Patience and forgiveness towards family are recommended. If they do not cease harming the husband and he cannot bear their actions, there is no sin upon him in keeping distance from them. However, he is not permitted to order his wife to sever ties with them. It is permissible for the husband to prevent his wife from visiting her family if he fears harm to himself resulting from their visit. The Malikis hold that he should not prevent her parents from visiting her, even if they are abusive, and that a trustworthy woman should accompany them during the visit.