data and airtime that just disapear

hi my name is roderick pietersen i am a prepaid customer cell number ********** 903 . My data and Airtime have just disapeared the last couple of days, i bought a 1gig data and R30 airtime. that disapeared after i made a few calls not equalling up to R30, I have WIFI @ home as well as work and i never had a problem, lately my data as well as airtime has just being disapearing. At 1st i though i might have used all my data and then it used all my airtime at a out of bundle rate, but then i bought another 300mb jsut to monitor, i also bought a R60 of airtime. at this stage a was on wifi all the time this afternoon when i checked i was out of data again and almost out of airtime i await your quick response

Thank you roderick Pietersen