Rain debit for a cancelled sim card.

I have cancelled/deactivated my sim card and i got a confirmation for my sim deactivation. And on the email it was to be deactivated on the 1st of August 2020 . But to my suprise i was billed a full R479.00 on the 1st of August. My sim is no longer active it doesnt even appear on my profile anymore to show it has been deactivated. I have tried countless times to get assistants and get my refund but its seems to be impossible. I have many tickets and emails to prove i have been trying but i am still not getting help or my money back. This is so frustrating because i cancelled based on how weak thier network coverage is. I want my money back. As far as I know Rain is a pay before use service, how does my account gets debited for the canceled future service.