A "paid-up" account is now a "handed-over account - Bad Service

I have been experiencing problems with a "paid-up" account since 2020 but Vodacom refuses to assist me to resolve this issue. I have been to Vodacom Kimberley several times since May 2020 (when I thought everything was in order) to date. However, the accounts department seems to be in chaos... A paid up account has now become a "handed-over" account! How can this be possible? I am being told that I owe R707-95 and I never received any statement of account, no letter of demand, etc.... No proper procedures have been followed and a phone call and one sms later, I am told I owe Vodacom money? This is preposterous and unacceptable. I will NEVER do business with Vodacom after being a client since 1990!!!!