1) You have to pay the bank: you cost the bank money by cashing checks that failed, and the bank paid out money to or for you without getting the money in it was supposed to. You are liable to the bank for the funds, and if you don't pay, they could sue you.2) You can sue this person to recover all amounts you pay or costs you incur. Of course, if she doesn't have any money to pay, that may not help: you could sue her, win, and still not get anything, because a court judgment in your favor does not make money appear where there is none.3) If you think she knowingly did this, passing bad checks intentionally is a crime: you could also look to press charges.