What should I do about my non-Muslim mother who cut ties with me because of my conversion to Islam, refuses to communicate, and suffers from a mental illness?

Allah tests believers to demonstrate their patience and truthfulness. One type of trial is hearing harm from disbelievers. The oppression can intensify if it comes from close relatives, as happened to Sa'd ibn Abi Waqqas with his mother, who wanted him to disbelieve. So the verse was revealed: "And We have enjoined upon man, to his parents, good treatment. But if they endeavor to make you associate with Me that of which you have no knowledge..." And in it: "...accompany them in [this] world with appropriate kindness." And as happened to the Prophet (peace be upon him) with his uncle Abu Lahab, who denied him. Therefore, a Muslim woman must remain steadfast in her religion and dutiful to her mother, even if her mother turns away or rejects her dutifulness. She bears no sin and is upon the truth.