Do we pay her back or no? Apparently we are our roommates maid?

It's like this..without an agreement you would still owe her money..to protect yourselves you need to sit down with them and renegotiate the terms...call it even on money owed up to this point and redivide the living expenses from this date on. Include the necessities like cleaning supplies and food in your negotiations. Make sure you get it in writing because verbal agreements are not valid in real estate agreements.