cellc took my airtime 3 times

i bought 10 cellc advance airtime on 24/07. i only made 2 quick calls to my husband. i tried to make a call later that day, only to find i dont have any airtime. i called them on 25/07. i was told a case will be opened as the consultant can see that my b i s covers my internet usage and my calls only costed a few cents and someone will call me in 2 working days. i got an sms on 27/07 that my case has been resolved. i phoned call c and even spoke to a team leader, who tells me i used the internet and thats where my airtme went. i told him that can never be as i do have b i s that covers internet usage. also i never download as i dont have a memory card. if that was the case, how was i able to use the internet the whole of saturday without any airtime? he could not answer me. i also stressed that this is the third time this has happened that i took notice. how many other times have they ****** my airtime, or other cellc uses as well. this is not on and i will take this further as their calls are recorded. previously i also had a problem which to date my airtime has not been given to me despite several emails from 22/06/2012 which i have. i will publish this everywhere if need be