contact the credit agency to find out how to attach a letter to the report. write what you have said and insist that it be attached to your credit report. Creditors who see it will know that the high interest cards are a scam and this was fraudulently charged to you. It may not change the number of your credit score, but it WILL change how many groups look at that score. Having worked on the merchant side of credit cards for a bank, I can tell you that letters like this can make a big difference.
Barbara, before you talk to them, contact a consumer credit counselling agency. You NEED to know how many outstanding debts she has and what amounts owed are BEFORE you start making offers. Once you send them money from your account, SOME groups will argue that you are then responsible for her debts. One way to avoid that is to put the money into her account and make her send a payment to them that very minute from her account via cashiers check, money order from the bank she uses, or to give her the cash to get a money order to pay the account. Do NOT send ANYTHING to the creditor with your name, account info, phone number or other info. ONLY her info. Even if you tell them you are NOT responsible for her debts, they WILL attach your info to her account and hound you. I had to get really ugly with one creditor when they got info on my inlaws and tried hounding them over accounts that we did NOT open or owe. It was ugly and hard to stop but we did eventually. My inlaws tried to talk to them, and then left their number for a supervisor to call them back and it all spiralled from there because the supervisor attached their number to our account and called them a few times a week to try to get $$$ out of them, even after we proved we did NOT owe them anything and they agreed and left us alone!
So do NOT give them your info. Tell them you are calling as her representative, and that is ALL they need. A consumer credit counseling agency may be your best help with this, and will at least be able to tell you how to get them to take a settlement. She likely has debts you don't know about, so before you settle with ANY of them, get copies of her credit report from all 3 agencies. You will then know what you are dealing with. It is an important step if you are to truly help her.