vodacom still eating my airtime balances

Good day, I recently raised issue of my vodacom airtime balances been depleted without me making any calls this happens every time I recharge which has discouraged me from buying large amount of airtime as it will end up been chewed and I will not get to use. The last time I raised this problem vodacom agent told me they had taken out the app that they suspect was responsible but I have monitored and this has not stopped. This is to report back that the problem of my airtime been depleted or disappear without me making any call is still happening. Kindly investigate why I am always losing my airtime and let me know so I can decide if to keep this service or look for others Thanks