Pay Back the Deposit

Office space was rented before we took occupation of the office from May 2014 and vacated at August 2015, we had paid a deposit.We engaged with her with my accountant and when it was time to pay She does not pay refuses to take calls and does not reply to emails.Went to the police to help deliver the letter of demand but the workers will not receive the letter and they say they do not know when she will be in the office.The police spoke to her on her cell phone but on realizing that it was about the delivery of the letter of demand changed and said she does not know Kim.