Customer constantly get given different stories

I have called Vodacom 3 times in the past couple of months and was told that my contract expired on the 11 April 2015. I called to give notice in March- I was told to phone back at the end of March- The last consultant I spoke to even advised me to take my SIM card out of my Ipad on the 30 April 2015 and re-insert it so that the prepaid can \kick-in"effective 1 May 2015.Today I phoned in to query what was going on and I am told my contract on ends on the 11 May so I will be charged until the end of May ??? Can someone who knows what is going on actually call me - I was under the impression that my last full payment on contract was in April"""