From the sparse question that you have written as to the facts of your dispute, if your former landlord is suing you for property damages at your former rental where there were health code issues never corrected by the landlord, you could cross complain against the landlord for overpayment of rent and accrued interest.I suggest that you may want to consult with a landlord tenant attorney or your local legal aid clinic about the matter you have written about for further guidance.