Will Allah hold me accountable for severing ties with my family – especially my sister – and for my reclusiveness, after a dispute occurred over inheritance, knowing that I was the first to maintain kinship ties before these problems?

Maintaining ties with one's sister is obligatory, and severing them is forbidden. If there is a dispute between you regarding inheritance, there is no impediment to taking it to court, but it is not permissible to sever ties with her because of the dispute. Her ill-treatment or injustice does not permit severing ties with her completely. You must maintain ties with her to the extent that it does not cause you harm, and this is the ruling for all mahram relatives (those with whom marriage is forbidden).