airtime lost within aminute

vodacom keeps on taking my airtime and when i call them they saying i should option out, as a client i feel that we should be sent such information so we know whats to be done when you loose airtime before using it,i can imagine how much they making from taking airtime from clients just after buying airtime,i have been with vodacom for the rest of my life but now the service is getting out of hand.i want my airtime back. i called you call center and the agent is saying they cannot refund me my airtime as if i know the steps they talk about.