Poor service from Vodacom Wonder Park

In January 2017 I went for an upgrade at Vodacom Wonder Park. I filled in all the paperwork and also asked for insurance on your phone, filed in the paperwork for that as well. In July 2017 I took my phone in for repairs. So a few days later I received an Sms from Rustenburg Vodacom Repair shop saying I need to pay R2400 . 57 for the repairs since I did not have insurance on my device. I went back to Vodacom Wonder Park to enquire about this and asked for the original paperwork. I waited 2 weeks for them to come back to me with an answer. The lady informed me the original paperwork indicate me applying for insurance. But the lady that helped me that day did not do the necessary computer actions. I was also informed the we are all human beings and it was an honest mistake made by her. My problem now is I was also informed that I need to make a payment of R703 before anything can be done regarding my phone for insurance purposes. My question is now why must I pay for another person's mistake? Who is going to make the payments for this outstanding balance Vodacom or the person who made the honest mistake? Your help would be highly appreciated.