My sis was friends w/someone for 8 years and then I started dating her daughter. After we broke up and some years went by my ex's mom was really clinging to my sis. I introduced my friends to the ex's mom and we all got along great. Then a few months later my former friend stole from my ex's mom and blamed it on me and since I wasn't around anymore I guess it was easy for her to believe I did steal. So now my sis is not friends with my ex's mom and I feel like I caused it because I introduced my friends to her. My former friends are still very good friends w/my ex's mom. I never even got a chance to defend myself either. So what do I do to try to fix the gap between my sis and ex's mom and finally defend myself against what I'm accused of?