Airtime dissapearing

i bought R55.00 airtime via my banking APP, made 1 calls of which all were less than a minute. i never had data, and i used my chrome app to search for Floyd Mayweather- i did not open any page from the search result, because i got the nicknames i wanted, i did not use my phone there after, apart from sending an sms.all this happened between 6:00AM to 7:00AM

i got to the office at 07:15AM, and my phone connected to the company wifi and i got all alerts from all my apps. What worries me is that Vodacom wants to blame my phone, the backround data and apps i have installed, but i am certain that i do not have backround data running, all my updates go off when am connected to wifi. i made 1 calls there after also less that a minute, when i try make a call i do not have airtime anymore.

this is a proper ******* from a service provider that claims to be the best