Support A Co-Signer In Need Of Relief

I am in need of help. I co-signed on a student loan for my niece to finish her junior semester and she couldn’t go back because her mother is stiffed her on tuition and now she’s stiffing me on the monthly payment. I’ve had some medical issue come up, which is making it hard for me to pay that bill along with my own commitments. I’ve threatened a lawsuit, but hiring an attorney isn’t in my budget right now. I’m able to make my own bills including my medical, but I don’t have it for the payment and I can’t get either one of them to make the payment and I don’t want my credit ruined.