Bad service

I have an account with homechoice they deduct on the 22nd of each last month their system had a problem I was only alerted on the 17th that it did not go through their reversed e debit order so I went to my bank to check whether it was mistake only to find that it was on their side now I'm told I have an overdue amount R1467 n it's supposed to be paid by the end of October of which I have already paid for October so I'm told that September installment is still I feel this is unfair to me because this is not my fault it's their system that failed n now this will reflect badly on my credit record and worse no 1 is willing to assist me.