Free airtime used for data

I recharged my airtime with vodacom and got two smses saying i got R75 free airtime. I bought a 1gig data bundle from my airtime that i recharged with. Not even a hour i tried to call a friend and it said my airtime was gone. I called vodacom call center and they said sorry they used my FREE AIRTIME for data why the hell do i put data bundels on if they take your free airtime for it. O sorry mam its in the Ts and Cs where is the website on the sms to say where to check that they use free airtime for data while you have a ****** data bundel loaded. This is false and misleading adverti*****t. Now i know why people change cellular groups. So people use the free airtime before they use it for ****** data!!!