Cannot get hold of Cellsure to cancel Vodacom Cell Phone Insurance!

I am completely unable to get hold of Cellsute to cancel the insurance on my mobile phone. I held for 45 minutes on their customer service line both yesterday and today and then the lines cuts out. I have emailed them and there is no response or acknowldgement. I feel sorry for anyone trying to claim from them and I would certainly advise NOT TO INSURE wth them if it is impossible to get hold of the,m. How does one cancel insurance with them?????!!! This is shocking customer service!