Contract renewal amount frustration

Good Day

So Imagine, being with a network for so long and they blatantly just decide to ignore your query. I took out a new contract the end of April start of May 2022, i understand now that I am still liable for paying the previous contract until September 2022. I asked if this could be settled, nope i should follow the payments, fine. In which case I just started making additional payments to my contract, in hopes of ending the old one sooner. However I have recently noticed that the amount charged does not add up. The newest contract will be R349.00 this was the agreed amount and the only amount I will pay, however when I subtract the outstanding contract amount added for now, it does not add up. I want someone to call me and tell me what is happening, what will by new contract amount be come September\October 2022. Why does the amount shown on the Vodacom App not add up. The response was that I need to call the sales department as the person could not answer me... Why should I call, to hold on for how long, to be sent from pillar to post? I have been with your company for so long, always renewing my contracts even though I initially decided against it, yet here I am still with you. If this is how you treat your long standing customers, then I see no future for us. So while I still have some contracts with you, can you try to provide me with an appropriate answer.

Regards