Debit order deducted while account is fully paid

Varsity college deducted money from my account which I have already paid for via EFT. This whole year and last year their debit order system didn't work so I paid EFT. Now suddenly a debit order went off. I want someone from the Online Campus to call me today and I demand a refund. This is the most useless business I have ever dealt with!! 🤬😡