Billing for services not requested

I have been experiencing this trend for a while now, If I buy any specific amount of data from them. They just decide to sell me more data against my will. 100megs at R3 for 1 day. 50mb at R5 until 23:59 despite me just having bought 250meg or still having 50meg. Am I not supposed to be asked to opt in for these extra services, instead I just get billed and given data I don't want, because shoving services down my throat that I didn't ask for is clearly *****ing from me. This is not upfront and honest business dealings. I tried to call customer service support to no avail, the number is not even ringing, Vodacom sucks. Am leaving them for the poor service and expensive data rates