Worst service ever

So once again I received my statement and again I'm overcharged. Vodacom what do I need to do for you to fix this issue coz honestly I'm so tired of going back and forth with you. How many times do I have to tell you guys that I never app**** for insurance yet I'm being charged for it? How many times do I have to keep calling and telling you that yes I did apply for an upgrade to a p20 smart but had to return the phone coz I did not like it? What do I have to do ensure that you debit the correct amount each month Yoh nna I'm so tired of you, you are the worst service provider ever. Im so drained shame I don't wanna lie. I spoke to a guy from your retentions team who assured me over and over again that they would debit the correct amount but if I call you I'm being told of the ridiculous amount, sort this out now please