complain about the poor service

i opened the list of my debit orders that were supposed to be debited from my account this month end, to my suprise there was a debit order of r9239.99 that i do not know anything about from vodacom, the debit order that is suppose to be debited from my account is r1034.10. i phoned the legal department and was told that they dont know anything about that debit order. that debit order is going to be returned against me and i am the one who is going to carry the charges, i am very much disappointed about the service that i have received from such a big company.