Missing airtime and data

Last night, before going to bed, I checked my airtime. I did a detailed check where they send the balances via sms. I had Monthly airtime R174.85, Recharge airtime R3.38, 417.79mb data until 05/09/2017 and a 30 sms bundle valid till 04/10/2017. Then I went to sleep. Phone was flat so left it off. Came to work and connected to the wifi, and I looked for ONE picture on the internet to send to someone via whatsapp to say happy birthday, and all my airtime is gone. The call centre agents are extremely unhelpful. Said at 10:56 am this morning I went on the internet and that is what I did with my airtime. Now, people who know me, know that I am very careful with my data, I never put my mobile data on. When I am at work I connect to Wifi so there is no reason to have it on. No one at Vodacom is even trying to help me. I regret upgrading my contract.