Refund from rain. Wrongful deduction

I cancelled my rain subscription 2 month ago. I haven’t used it for 2 month, don’t even have the SIM card. This morning I wake up seeing that rain took R479 from my bank account for the month of June. And on the invoice it shows that the data usage was 0. Rain says they don’t like giving nasty surprises. Imagine waking up seeing that R479 has been deducted from your account and now you cannot afford to pay your rent because rain deducted R479, after they stopped deductions end of April. Will they give a refund ? I desperately do need a refund because this is so unfair. I regret even activating the rain sim because it never worked properly and the internet was slow on the few occasions I did make use of rain