Over debit with no explanation

I'm on the Classic Core plan and the monthly deduction for this plan is R 2,064. On the 1st of November R4,454 was deducted from account.

I contacted Discovery to query this and they couldn't give me an explanation. The amount of R 4,454 doesn't even reflect on their side. They tell me they only deducted R 2,064, so now I have to submit a bank statement as proof.

Please explain why R 4,454 was deducted and please issue me a refund