being told u owe but no supporting documents

I phoned *** on several occasions requesting for the balance on my name i was told i owe R1513 i requested an invoice showing how that amount was calculated. Im still waiting i emailed [Email Removed] 1st time i was given the october invoice showing R-89.93 which i then responded that i need statement showing how they got to R1513 emIl was deleted without being eread i semt anpther 1 today it was read no response. No 1 is taking accountability. I phoned today spoke to Muzi who couldnt help i asked for his supervisor he/she was not available. Was put on hold for 27minutes an then the call was re routed to the call centre. How difficult is it to provide an invoice for a forced service that you are forcefully proving to South African people?