Cancellation

I called Autopage on the 16 April 2015 to advise them that my cell phone contract ends on the 11 May 2015 and I want to cancel and have the number ported to prepaid. I spoke to Thabelo and she advised me that it will only be converted to prepaid on the 28 May 2015 due to Vodacom's procedure. She also advised me that my last billing will be 31 May 2015. I called again today to confirm if everything is in order for the cancellation to go through. I had a previous experience with them earlier this year so I did not want the same problem. I spoke to Arnold and he said that my last billing will only be 30 June 2015 because they did not get any cancellation request from me. I advised him that the calls are recorded and only then he said that it will be cancelled and I wont be billed. he then told me that he was going to transfer me to another department so I can confirm what message he had stated on the system. I was transferred to Mulalo and she informed me that she cannot see the message that he had put for cancellation. please can you help me to get this contract cancelled at the end of this month and i do not be billed again in June. No one at Autopage understands how they operate.