Paid for no service

I've had very little to no support from this company when I expressed my grievances...I recently paid my monthly subscription of R550 but the payment was late, when you have late payments, they turn off the WiFi.. Since paying on the fourth, the owner has explicitly refused to turn back on the service for which I had paid. After a few days of any form of communication from him, I asked for a refund so ii can look for another service provider, which he rep**** he will process the money on the day..it's been two days and he's told me he has every right to keep the payment since I was late..

Please help!