Handing my account to debt collectors

i made arrangements with them to deduct money from my account NEDBANK on the 20th each month and yesterday i called them to ask for the balance that i still owe so as to be able to pay extra but let the debit order of R1000.00 continue so as to finish as quickly as possible. i went to my bank to see if there was a returned debit order and there was nothing. So Vodacom say i did not honour my arrangement yet they did not load a debit order on their side meaning i made arrangements and they did not adhere. now my name has been take to collectors and will be painted incorrectly on the credit score. i called *** and spoke to Thembi which she already judged me as a non payer and dropped the phone on me. called again and spoke to Penelop and she said she will escalate to legal not knowing if i was just being brushed off. this is the only channel that i know and hope to get a quick response. These are one of the reasons for me to leave Vodacom (yet my heart is still with) as i cannot accept BAD SERVICE