Kinship Help- Bio Mom Attempting Contact -First Time Post

ok- This is a very long story but I will try to make it as short as possible. My sister who is 11 Years older than me has had a Huge Drug addiction her entire adult life. Heavy Heavy Drugs. I have tried everything in my power (Sincie I was 16 years old) to help her with her problems but nothing has ever worked. When I was 19 and she was 30- She had a baby girl. Thru the years her drug use actually got worse. My then Boyfriend and now husband and I have had custody on and off the babys entire life. We would have her or 3 months and the courts would give her back, we had her for a year when my sister was in Jail - and the courts still gave her back. Whe the little girl was 7- I Vowed that this can not keep going on. I promised that I would do everything in my power to keep her for good if she messed up one more time. Well- One day when my "Niece" was 8 she walked in from school to see EMT reviving on her OD'ed Mother. She was placed in a foster home. In the past, I was always contacted before the state got envolved so she would immediatly come to me. But since my sister was unconcious and unable to give volentary custody to me, they placed her in a foster home. Since she was "A child of the state" I couldnt simply get custody this time. My husband and I had to become foster parents. Since it was taking too long due to us living in a diffrent state, my husband and I moved 1500 miles to their state. We did everything we had to in order to get custody. It took 4 months, but we got custody. My sister didnt comply with anything she had to. She failed every single drug test and didnt go to any meetings. she wasnt showing up for visits and eventually had her visits revoked and ultimatly her rights were terminated. Since she wasnt being an active part of my "Niece's" life, I cut all ties. We would only see her on court dates. After her rights were terminated, we had no contact. We adopted my now Daughter. She chose to take our last name. WE had a baby thru this all and she asked to be called SISTER to the new baby. She is now calling us MOM and Dad. She is an AMAZING youg girl and now she is 15. The adoption was 4 years ago. MY family (For some unknown reason) Still speaks to my sister. I have learned that I cannot control what other people do - I can only protect my family. I have asked all members not to give any info. No photos, no updates - nothing. Recently she came around the family begging for money. She is now facing jail time for drugs and robbery. She was being evicted. The one thing I actually respected of her thru all of these years is that she left us alone. She never tried to contact us at all. BUT ..... All of a sudden she told 2 seperate family members within 3 weeks that she contacted MY Daughter on Facebook. She said that they were speaking, I found out, and I punished my daughter. PROBLEM : IT NEVER HAPPENED! I had a long long talk with my daughter, and not only did she never get contacted but she expressed how she never wants contact at all. She remembers all that she has been thru. SHe rembers all that I know plus everything that my sister WAS NOt Caught Doing. These are not good memories. So...... What can I do? This was a closed Adoption. I live 1500 Miles away from her and she is faceing jail time now. But I cannot put anything past her. She has nothing to lose. But what is really bothering me is I dont know why she is Lying about this? Why such an elabrite lie? She is a Pathalogical liar, but she has recognized all the damage she has caused in the past and I cant believe that she is dragging this little girl thru this all over again. Any Feedback?