Billing for no service

My R250 month-to-month sim card was delivered on 29th of March 2020 and it had no INTERNET/OFFLINE connection since then! I have cancelled my contract and got an SMS confirmation saying "Cancellation for SIM 1 has been scheduled for end of this month and your final payment for this SIM will be processed on your selected date next month"

I have tried contacting them and they don't respond to my emails and their phones are forever on hold.

All I need from Rain is a REFUND since I didn't even use the sim card!!