Worst service ever: No accountability and lack of communication

Firstly i signed up for a package that was R675 , all was well router delivered. Month 2 my invoice comes with R910 that I'm owing. I send emails, tried calling help desk no assistance. I even opted for cancelations with still no one calling me. 3rd month I still receive invoice of R910 and did not pay it. Rain calls now because my account is 8n arrears, I need to understand how am I being billed R910 and "according to the agent it seems like I upgraded" WHEN, HOW AND BY WHOM WAS THIS UPGRADE DONE?????. I have been told my issue was escalated to billing department, and to date I'm still waiting, I keep on getting calls about an outstanding account, WHY IS MY ISSUE NOT BEING ADDRESSED??? RAIN PLEASE GET UR BILLING DEPARTMENT TO CONTACT ME, AND PROVIDE ME WITH PROOF OF THIS UPGRADE REQUEST SO THAT I CAN TAKE THE MATTER FURTHER