Unfair service

I bought airtime for R12,00 airtime yesterday they said they have given me free R12,00 which is not true coz when I tried to call using that airtime it can't go through,today I bought R5,00 they do the same when i call the call centre imagine they told me that they use both airtime and data on the internet .imagine I have enough data and they are using my airtime too us this a ******** game ,Telkom wen u use internet if data finish they pause ur internet connection but vodacom don't bcz they wanna **** us .its totally unfair