80c That Vodacom Forgot to Deduct

I cancelled Vodacom 3G contract Jun 2013. Feb 2014 I found out I had bad credit record, I owed Vodacom 80c only, 8mnths past due. I phoned Vodacom. With a debit order how could I be owing them? Why were they damaging my cr record for 80c. She called her Manager. Account settled.<br> 1yr later applying for bond, 80c still on cr record, still not corrected. Bond consultant says \banks view this in a very serious light