Rain billing department does not understand their own invoices

I bought a rain sim card in January after checking whether I have coverage. The site told me I am in a 5G zone. Great. I registered a rain sim card on the 28 January 2021 and had it RICA'd.

I then purchased the unlimited service plan for R479 per month which is post paid but your card is debited immediately.

To my disappointed the coverage was poor, I could hardly access the ineternet or stream anything, I then contacted the customer service via social media and they told me to do all these speed tests, which were frankly quite useless asthey did not improve my network speed.

Fine, I then cancelled the service in February.

On the 2 April 2021, my account gets debited with R479 and when I escalate this to customer service, they tell me this is the post paid bill for February yet when I log into the site under my profile, I realise that I was invoiced for the month of March and yet I had cancelled the sim in February mind you, there was hardly any usage for the month of February.

All I want is for my money to be refunded, and an email confirmation that shows that my details have been removed off your billing.