I want my money back

I was in conversation with a “Vuma” company. I wanted to get services for WiFi installation, I already paid for the installation fee of which the person I was in contact with advised me that it should be an immediate payment into an ABSA account. After paying the R400 installation fee he now mentions that I have to pay R350 for the activation, and that is when our disagreement started. I told him that he should come and install the WiFi first before I pay the activation fee but he disagreed and was actually forcing me to pay the R350, so that he can activate. I am really not sure if this is a **** or what, I asked for a refund then he told me that I should go to head office in Johannesburg. I need my money back because I tried contacting the business but no one is getting back to me.