It is obligatory to sever all ties with non-Muslim and even with Muslims who do not cut their relations with non-Muslims.
Indeed, this is unfounded claim. It is known that the Prophet (PBUH) lived with polytheists, Jews and Christians and all of them attested to the Prophet’s good manners and morality. The Prophet never fought them except after they showed open hostility to him and prevented him from practicing his religions in peace.
The biography of the Prophet indicates he had relationships with people of other faiths and even cooperated with them for public affairs of the society.
Moreover, how can one have such false allegation while it is known that the Prophet used to visit his Jewish neighbor in cases he was sick? Once a Jewish woman invited him to have lunch, and he accepted the invitation for food.
The Prophet has never cut his relationship with non-Muslims nor did he order Muslims to cut their relationships with them. The Messenger (PBUH) was the most pious person and the most knowledgeable about the Book of Allah, and this was how he practiced Islam. So, should we get the teachings of our religion from Allah and his Messenger or from those who distort Allah’s religion?