NO REFUND AND NO FEEDBACK RECEIVED . PLEASE CAN YOU TREAT THIS AS URGENT!!!

I vacated Meredale Heights premises on the 1st of March 2019 and an inspection of the unit was done on the same day, no faults or damages were found on the unit and the body corporate advised that I would receive my refund on the 20th of March as they would need to get the last billing statement for the utilities. On the 25th of March I received an email from Nino stating that I was owing one month's rental and I told him this was impossible as my monthly rental was always paid up to date up until the very last day of the month that I vacated the premises. I then had to go as far as providing Nino with proof of payments for the entire lease period, for some reason they could not locate my rental payments ( and this was not the first time this has happened, on the 4th of Feb 2019 Karien Randles sent me an email saying I am in breach of contract for not paying the last month's rent, I was really amazed at this as I had made the payment a week before he/she sent me this email. If he/she had checked his/her statements before sending the email she would have noted that payment was made already before she sent the email! It really makes me wonder how the accounts are being done at those offices that payments are not being located and allocated correctly) to the point where the tenant actually has to provide proof of payment to show that the rental payment was made. Nonetheless, I did not hear from Nino after the 25th of March until I eventually had to take it upon myself to follow up with him on the 28th of March 2019, he apologised for the delay in response and advised that my refund would be processed on the 1st of April. I have not yet received the refund, I followed up with Nino again on the 2rd of April 2019 and have yet to receive a response. Please can you advise when I will receive my refund as promised by yourselves in writing on numerous occasions!