Property Manager ignoring my calls and not receiving my refund

I have rented a warehouse in Hermanstad ,PTA which broll is the property manager and due to covid i had to move out of the place. For almost 5 months i have been struggling to get back my refund. I have been dealing with one of their Property Managers "Jaco", at first we have a very good working relationship but the moment i notify them of me moving out everything changes, i have been making endless calls, sending emails,whatspus but he just ignored me.All i want to know is why i they ignoring me,why am i not getting my refund back yet they keep sending invoices but when i call them to enquire whats the invoice for no one is responding. This is unprofessional for a company like Broll.