Handed over status removed and make payment arrangements

I took a preowned Iphone with Vodacom cellucity last year April and their consultant told me that we have to activate a debit order for payment as it is my first time taking a product with them. I agreed and asked if will I be able to go make my own payment at any of their stores, she then said no . Time went by without Vodacom deducting , I went to their store and they told me they had an issue with collections and I then asked to pay . They still refused me to do so, even after I’ve showed them emails of invoices asking me to pay and stating my arrears.It has come to my attention that my account has been handed because I’m in arrears of R2860 of which it is not my fault and I’d like them to fix that and start deducting.