ripping clients off

My contract is expiring today. The benefits of the contract like airtime and sms's expired yesterday evening. To my surprise everything in using the R100 airtime I purchased has been whipped out and my balance is Zero. <br> Why did they do that, I have called Cellc a thousand times cancelling this contract and no one informed me about such a thing. Furthermore why is it interfering with the airtime I purchased by myself. I bought 2g as, I see that has also been whipped out. I need answers