I have a sister that was my best friend for years and she turned her back on me when I became very ill?

and had to have brain surgery. A few months later she and her husband asked me for money to purchase a truck for their son. She then told lies that they bought the truck for him and began to spread lies saying that I was mentally ill. Which is a bald face LIE!! I have alienated myself from her and the rest of my family because her lies has persuaded them to mistreat me also. So, I have cut all ties to all of my family and am in my 2nd year of college. My health is better and when I graduate my son and I plan to move out of state and never communicate with any of them anymore.