Unable to help clients

After living in one of their apartments for 6 months I moved out of the apartment and did the proper inspections where everything was marked down correctly. A month later now and they refuse to pay back the deposit after we have been calling multiple times. They keep stating they will pay the money but a month after I moved out I have not had any contact from them unless we call them. They had me certify my bank account to prove that that is my account and after providing the documentation needed they have again failed to contact me or pay the deposit.