Vodacom: Airtime Disappearing!!!!

I am absolutely horrified with the appalling service of Vodacom and total incompetency. My airtime seems to "disappear" from my Vodacom account - I definitely did not use it. I am on a RED 2GB 400min TopUp plan and keep on getting messages from Vodacom that I ran out of airtime. On 16 Jan 2023 I bought R100.00 of airtime. I again got a message on 25 Feb 2023 stating that I ran out of airtime and bought another R100.00 of airtime. Today (28 Feb 2023 @ around 15h37) I got another message indicating that I ran out of airtime again! Less than days after my last airtime purchase. The call log of my iPhone indicates that the total duration of all my outgoing calls from 25 Feb to today was 27 min 45 seconds. It is very clear that Vodacom is "*****ing" airtime as I have definitely did not use this. I have been on the line today with a Vodacom Customer Care Agent who is clearly totally ***********. I requested to speak to the Vodacom Customer Care Team Leader who indicated that she is not available. The Vodacom Customer Care Agent then went ahead & transferred me to the Vodacom Subscription department who told me that they cannot assist. Another indication of the total incompetence of the Vodacom Customer Care Agent. I requested that Vodacom forward me a full report with all calls (incl duration) to explain how the 400 mins airtime (which is part of my contract) as well as the additional R200 airtime bought on 16 Jan and 25 Feb 2023 were used. I also requested that a Senior Vodacom Manager call me wrt this matter. I had the exact same issue in 2022 and then the Vodacom Customer Care Agent explained that this sometimes happens, and he did a reset from his side and requested me to take out my SIM card and put it back after a few minutes. I have not received any explanation for the above from Vodacom and no one has called me wrt the matter. SHOCKING!