No, no, no.
You are a business. You have a contract. Tell her clearly what you were willing to help short term over summer but you can not forgive debt of whole month fees. That is not your contact. Be clear that this is not option, that you sympathise but you should not be hung out because she managed income badly. Be clear that if need be, you will take her to Small Claims for your months fees. Three days is not even close to the mark.