money *******!!

Talk about ****************. So i had R239 airtime in the morning. When i switched on my phone, all of a sudden the airtime has disappeared. I called mtn for clarity and all they could tell me was that i probably downloaded something, funny thing is i cannot even download anything from this phone. STOP *****ING my airtime and hoping that i won't notice. I need clarity as to what happened to my airtime which i did not even use!!!!