If you have been returned your full security deposit after move out by your former landlord and afterwards you were sent an invoice by your former landlord for repairs and maintenance to be paid, I too would question the appropriateness of the bills. First, you should not be required to pay for maintenace costs of the rental. That is an obligation that the landlord should have.As to the claimed repairs, I would write the landlord a letter asking for details as to the repairs with back up invoices for such. Keep a copy of the letter for future need and use. I suspect that the "repairs" are in reality charges for normal wear and tear to the former rental that you should not be expected to pay for.