airtime taken for Internet but i have data

<p>This started yesterday i bought R10 airtym they i payed advanced R6 i had R4 n R20 bonus airtime. As soon as i get to work i switch off ny ata n connect to wifi suddenly later on during the say i found out my airtime is gone but i didn't bother with that so i did advanced airtime of R5 minute immediatly after that i bought R3 20MB daily note before i took the advance airtime i switched off my mobile data after purchasing data bundle i switch them on later on i try to make a call my airtime is gone i called the call centre Hlengiwe told me that she doesn't understand why would the internet or any connection eat my airtime and data at the same time. Can you guys please Check on this because now im scared to recharge because my airtime goes missing</p>