airtime going missing

yesterday at 16:22 i bought R10 airtime i was owing you guys R4 so i had R6 airtime left i borrowed R15 from advanced so my total was R21 so i wanted to buy whatsapp bundle it told didn't have enough fund when i check i have R16 airtime but didn't mind that i bought immediately R20 airtime while i have R16 in my balance ,you guys took R16 since i borrowed R15 advance so i had R20 left i bought whatsapp bundle it went through now i was trying to call someone it stated i don't have airtime when i check my balance i have R0.00 and even the bonus airtime is gone while all this is happening my mobile data is off. i called at 16:53 spoe to gugu she told me that she cant see anything at moment i must call after 30 minutes since i was busy i called back 19:56 spoke to this girl called kedumetsi she told the was background updates , updates do run even if your mobile data is off that shook me i wanted to speak to the team leader (denzilin Adams) she told me the same thing this shook me because internet on my phone wont run when my mobile data is off , she is telling me that with Cell C it can , oi know that's not possible when you don't have internet connect no internet connection can , please assist and educate your customer service people because now i'm afraid to buy airtime because my airtime disappears and i want this to be sorted i want my airtime back reference for that call was ********** 322