Deposit not paid by national letting

My name is Naniki..i am writting on behalf of my mother, she entered into a leasse contract with national letting in Auckland park in 2015 and renewed the contract in 2016 which ended in 2017 January 31st. She waited for the deposit money to date she has never received any amount to date, she did even receive a notification on how the deposit money was used. The person who was in charge of the account was Lauretta in Auclandpark national letting office

Please help on this regard