Vodacom - Disappearing Unused Airtime

I use Vodacom prepaid data bundles. I'm on a 20GB per month sim card package. I normally buy airtime and convert it to data bundles. In the past two months, I have lost close to R 800 airtime that disappeared before I could convert it. In jabiary 2025 I went to Vodacom Bluff to lodge a dispute. They checked my sim card and told me that there were 'subscriptions' that were deducting which I never signed for. They told me that they have stopped them, it will not happen again. It has happened again! On the 9th of February, I uploaded R 150 airtime with the hope of converting as soon as my monthly data depletes. It has since disappeared and I had to purchase airtime again on 12 February to get data bundles. This is *******ion, daylight ******* and a rip-off.