Unauthorized debit order.

Just woke up to a medsage about a debit order for the amount 1447, I have canceled my contract last year, called thier customer service to enquire about that and was told the account was opened in September, yet they can't tell me who opened it and where, why can't telkom pull on their records. Why should I go up and down for something I did not sign up for? And what happened to debit order mandate? Why was I not make aware of this unauthorized debit order. This is very upsetting and it ruins one's mood.