Cutting off ties with a non-Muslim sister
Praise be to Allaah.
Because of the insults that you suffered, there is nothing wrong with what you did, in sha Allaah. This would not be considered as "breaking family ties", and it may give her the opportunity to think about what she has done.
Al-‘Allaamah al’Safaareeni, may Allaah have mercy on him, said in his book Ghidhaa’ al-Albaab: "Ibn Abi Hamzah said: ‘The ties of kinship may be by money, by helping at times of need, by warding off harm, by meeting them with a smiling face, and by praying for them. The general meaning is that one helps them in good ways as much as possible and helps them to resist or fight evil as much as possible. This is the case if one’s relatives are righteous, but if they are kaafirs or are wrongdoers, then cutting off ties with them for the sake of Allaah is how one maintains the tie, on the condition that one tries to warn them, and tells them that the reason for cutting the ties is because of their deviation from the truth. At the same time, the connection of making du’aa’ for them should remain, and you should pray for them in their absence that Allaah will guide them to the Right Path. (al-Tuhfah: Ghidha’ al-Albaab, 1/356).
And Allaah knows best.