Deposito payback

I just want to know if it is good practice of them - I hired a home from them in Ermelo for more than a year-i went to them to give notice for end of april 2019-they asked me to stay in the house untill they get new tenants because the owner dont want the house to be left open-i asked the agent if i will loose my deposit by staying-helping them out and he said no-i told him i need the deposit money-end of may 2019 we moved out but till today never received my deposit or any explanation whatsoever

Please inform me

Regards Hetta