swindled

State is California. I did a favor for my friend and open a bank account so she can deposit her checks, and didn't want her husband to know. I got like 20 letters from the bank that I owed $7,000.00 in bounced check fee's and fake checks. The checks were written and deposited and drawn on. Not from me but her. I went to her house and she refused to make good on it. She said I can't prove a thing that she did it. Now the bank is taking action against me. Is there anything that can protect me by law with this situation? i trusted that she was honest with me.I also went to the bank, and the customer salesman acted like I had a desease.He said I would have to make good on this before they send it to collections. I am sure that's where it is now, but it's not fair for me to have to pay that money back when I didn't even have it.Please Help.
Chicky