Is a young man held accountable for the severed ties with his maternal half-siblings, especially since they were the ones who changed their phone numbers or refused to visit him, which led to his ignorance of their whereabouts?

Maintaining kinship ties is obligatory, and severing them is forbidden, based on the Almighty's saying: "So would you, perhaps, if you turned away, cause corruption on earth and sever your ties of kinship?" and the Prophet's (peace be upon him) saying: "A severer of kinship ties will not enter Paradise." The minimum degree of maintaining ties is abandoning estrangement, offering greetings, and engaging in conversation. Therefore, call your brother on the phone and look for your sister's address. Know that the possibility of coldness, patience, and responding to ill-treatment with kindness are necessary matters. The Prophet (peace be upon him) said to one who maintained ties with his relatives while they severed him and treated him badly: "If you are as you say, it is as if you are feeding them hot ashes, and there will always be a supporter from Allah with you as long as you remain upon that." If you are unable to establish contact, there is no blame upon you, for "Allah does not burden a soul beyond its capacity."