Is severing ties with my parents considered disobedience in the event they continue to hurt me and refuse to communicate with me?

It is strange for your parents to harm you and cut you off, unlike your siblings, merely to provoke each other. If this is the case, then your parents are unjust and severers of kinship ties. However, this does not negate their rights over you, nor does it permit you to abandon them entirely, but only to the extent that removes harm from you. Be keen to honor them and maintain ties with them as much as you can, and strive to appease them with kind words and good deeds, for responding to evil with good brings affection. If you exert your utmost effort and they persist in abandoning you, then there is no sin upon you.