Nightmare to cancel - took money that's not theirs

Called on 2021/11/25 to cancel my contract for 10 Dec as we were moving to an area without Rain 5G. Was told I have to call on the day as it's post-paid - so they would charge me pro-rata.

Called on 2021/12/10 as requested. Lady first gave me nonsense that it'll only be cancelled at the end of Dec. I told her that I was told on 2021/11/25 to call on this day and that they cancellation would be immediate, and I have the call recorded. Said she'd make a special note so that it is cancelled immediately.

31 Dec, I get debited the full R999 for the month and not pro-rata (1 Dec to 10 Dec) as promised.

So I call on 2021/12/31 to complain again and ask that they reimburse me. A week later I've heard nothing, not even an email.

I've had 3 or more people sign up with you because of my referral - how I regret it now. Ridiculous service and it seems Rain enjoys keeping money that's not theirs. You've lost my trust.