Deposit refund

I moved out of the flat end of February and I was supposed to receive my deposit refund within 21 days and until today I'm still waiting. I have been reaching them on call and email but the response is always "will check and get back to you". Now the office is open but no communication from them, when I call, the person responsible is not in the office. What must one do to get help? Everytime one must get what is due to her it takes for ever but skip a rent, they call throughout the day. Another thing is even going to the office is not even a solution but waste of money and time which I don't have because you get there and your told lizelle is in the meeting. Zelri you have beautiful flat but your service is very disappointing.