im so disappointed with the service

Today i recharge my airtym n i loaded 20mb of data bundles and there was still an airtym dat was left on my account and i made 1 phne col.. and the remaing of my airtym waz R7,80 i then started accessing my social networks as per norm knowing very well that it wil deduct from my data bundles, i then checked my airtym as i wanted to make a quick col only 2 find out that m left with R3 and some change i then call through da customer care and i spoke to Lerato who had a stinking attitude and she told me 2 phne after an hour as the system has not updated as yet. I then called again as i was adviced the agent by the name of Deneo gave me wrong information advising me that my airtym was used up on whatsapp while viewng my contact pictures.. it suprised me coz it not the first time im using data bundles on whatsapp and viewng people's pictures and it never took from my airtym so what i wanted 2 know why today why was i charged from my data and my airtym?