Hon, she is lieing to you and your husband...she has lied many times before and will continue to do so, it is what active users do. Think about his, how many times has she told you that she has quit using, months ago, was it true...no.
Your enabling has accomplished nothing, and, will not cure or save her, she is an adult, her recovery is totally up to her, until you let her fall to her knees, she has no chance of getting back up on her feet and becoming a responsible member of society.
I know that you want to help and that you are in pain, however, all her the dignity to find her own path in life, enabling is not the answer, it only delays one from reaching their bottom. I agree with TJP step away, go about the business of your life.