Incorrect billing

Again it is me and Vodacom. When will this end? I have been a Vodacom client for probably 13 years. And for the past year it is the one problem after the other. Billing errors. Overcharging etc. This week I query my bill as it is higher than usual. I get informed that each month since May I underpaid. EVERY MONTH I PAY WHAT CALL CENTER AGENTS TELL ME! Last month I actually went into Vodacom shop in Irene and paid there. They verified on the system what my bill is for both accounts and I paid cash. But still I show arrears. WHat is happening with your billing system????<br>