Vodasure is fleecing me

Before relocating to the UK, I moved my paid up Vodacom contract onto a pay as you go basis, as I only need to keep my SA number going for occasional banking transactions. From here it has proven impossible to cancel my handset insurance, despite making numerous calls and sending emails to the suggested email addresses. None of the short self help numbers given really work from overseas and Tobi is no help whatsoever as my issue falls outside the very narrow range of topics he can help with. I am still being billed over R200 per month by Vodasure for an now very old handset. I need this to stop, but cannot find a way to get it done.