Vodacom ripped me off!!

Vodacom is probably the biggest false advertisers on the planet!!!i bought airtime,got"free' airtime with that purchase,my data was switched off,i immediately bought data, received a message to say my data purchase was successful,then i switched my data on,used the internet knowing i bought data,when i checked my balance the "free" airtime was gone,i phoned customer care,a lady told me that the "free' airtime depleted because i used the internet before the data i bought kicked in, remember i got an sms to say the data i bought was allocated,now another agent phoned me and FIRST told me that the system will use the free airtime before it uses my airtime,but i had data,why use the "free' airtime???then he changed his story and said before the data i brought kicked in,it used the"free' airtime!what a *******!