Unknown billing

My family social grants is been deducted with airtime ever since last year.We never lost our identity documents but this is getting worse.Everyday i buy food with this money they are busy buying airtime everyday.Im ashamed what they are doing.Because we are all South Africans.My contact is *** i have been phoning them no answer no response and their local office they gave me billing i dont know.They are saying its not their problem.