Vodacom *****s Airtime

I have normal prepaid with Vodacom and buy my airtime. I do not load much airtime because I do not make long calls. I have a router with a data sim card and do not need to buy mobile data. I also bought a Whatsapp ticket for Whatsapp purposes only. The thing I do not understand is that the minute I switch on mobile data when I have zero mobile data to use Whatsapp, I get a 10 Mb data refill, which is deducted from my airtime? What for? What is the use of a Whatsapp ticket then? I will not let Vodacom decide for me when I need data. I have tried to opt out to no avail. I have set my limit for data usage from airtime to R1 and even to R0? I have tried to phone Vodacom but I am not offered the option of speaking to a consultant? They are forever having “high caller volumes” (sounds more like a permanent voice recording)? When I opt out of the data refill the sms always says I will receive an sms to confirm my request but that never happens? So now I refrain from buying airtime in case I lose it to data refill. And what about all the airtime I have lost? Will Vodacom refund me? I don’t think so? This is total nonsense and they are robbing the public again…