Incorrect Migration done by Vodacom

I was contacted on the 30th of November by Vodacom with a deal to migrate my Smart M+ package to a Red 2GB 400min package at R569 and was told that if I changed my mind I have to cancel this by the 30th of November (the same day). My package was changed, within 30minutes, on the My Vodacom app to a Red 2GB 400min TOPUP at R599 per month. I immediately contacted Vodacom to let them know I was migrated to the incorrect package. After 2hours on the phone I was told that the package will be reversed to the Smart M+ package. I received an SMS today that the "upgrade" has been reversed, but nothing changed on the My Vodacom app. After another 30minutes on the phone I'm told that the reversal will only take place on the 31st of December. I will have to pay the R599 and be inconvenienced with a top up package for December due to a mistake Vodacom made. This is unacceptable!!! Why do I have to pay and be inconvenienced by a mistake made by Vodacom??