Airtime and Data dissapearing

Lately when I recharge my CellC account the airtime and data just dissapears. Today I called cellc customer care (140) and the agent said it's internet downloads, I told him I haven't been using my pone all those times and he said he will transfer me to technical support. After holding for a a minute I then got the prompt to rate the service, I was never transferred to technical support nor did I get any assitance. The agent's attitude was that it's my internet usage consuming my credit whereas I was not using it. I have been using Cell C for years and I know my usage habits, data and airtime cannot just dissapear without explanation.