Disappearing air-time

I'm being sent from pillar to post: I want to know who gave authority to have monies intermittently deducted from several of my pre-paid accounts, under a code "+947", even when the sim cards are not installed. I have lost several hundred Rand just in the past few months. I wonder how many subscribers are fleeced this way. Nobody at Vodacom can tell me what it's about, other than its an international sms. Joke is, the sim cards in question are usually installed in embedded controllers which can only send and receive specific messages to fixed local numbers. The latest reference from Vodacom which led nowhere, is EC-0C7H-2V63UP . I am about to take up the matter with ICASA.