It was at this point you should have done your homework. Above you are admitting that assumption is indeed the mother of all f-ups. Good on you for helping others (below) and bad (or retarded as you rightly put it) for not thinking things over. And good on Vodacom for refunding you even though you messed up.
I hate Vodacom as much as everyone here, but this one is squarely on your shoulders.
Here is two nice quotes that read like testimonials:
"I've been wanting to take advantage of the same bundle, but in my once off/monthly data bundles on the vodacom site I only have the standard/advance options at full price... Based on your experience there's no way I'll click or even send their suggested SMS activation method before it displays the reduced price on their site for activating the service." - Vio
"Phew...
I almost made the same mistake! Luckily I now read this thread...the only reason i have not done this is because i tried activating the service via the full website, and noticed that the service cost full price.Made me a bit suspicious, so I held off on buying. Lucky me..." - hannodewind
You've already correctly concluded that I'm retarded, what the hell do I know about "doing my homework"? The last "homework" I did was at school, many decades ago, and I always got it wrong and got into serious trouble because of it.
What exactly is this "homework" that you wanted me to do? Maybe something like the following:
1) A comprehensive study on the display, menu and functional inconsistencies and disparities of the Vodacom web presentation in particular over different sites and over different promotions.
2) I Could have read the book: 101 ways your SP can fool you into paying them exorbitant OOB charges, and how you can avoid it - for dummies.
3) I could have just read this thread, then you could have added me to you list of "testimonials".
On the other hand I must admit I
always "do my homework" when I go and "Top Up" with fuel at the petrol station, to prevent ending up with a tank full of Kerosene Class A Jet Fuel.
And I always "do my homework" when I go to the shoe store to buy a pair of bunny slippers, to ensure I don't leave with a full Alpine Skiing Outfit plus skis.
If after all this I had still more of my copious spare time left I can read the book: The deep inner mind working and and psychological manifestations of individuals that cannot help themselves but to defend the indefensible.
PS: If they don't reverse the data-bundle charges (they haven't yet) I'll sue them. I just know they won't reverse the OOB charges, because they just don't, ever. It's not in their nature.