I won't repeat what everyone said. Basically you can't sue if you signed this. You do owe this money just as much as she does. Sucks but true.
Instead of killing days while the payment is STILL due trying to figure out how to reach your daughter, I strongly suggest you call your lender directly and be the borrower and explore payment options.
You can make this easy on you WHILE you wait on some sort fo exit. Ask for an online account to view and manage your account, view interest, make payments etc. Tell them you're the one who's going to be making payments and need all the options the primary borrower has.
ASK ABOUT FORBEARANCE AND GRADUATED PAYMENTS.
My monthly payment is supposed to be $700 on my 4 student loans. I skipped an entire year with positive credit reporting because i requested forbearance. Then i got on a payment plan paying itnerest only. Now I make partial payments of $250 a month.
All the while my credit is just fine, my loan is in good standing, and I'm in CONSTANT CONTACT with my lender.
It's time to be aware of what they can do to hurt your credit score and personal well-being. Your assets, your home, your car. Be their friend, trust me.
As long as they see you are WILLING to fix this somehow, but just can't, against your will, they WILL work with you. They do all the time. Ultimately they want you to comfortably pay them their money. They don't want expensive and time consuminf lawsuits either - they're people too.