still being billed for a now cancelled contract

I was advised to cancel my contract on the 6/11-that is when my contract expired-i called in many times-on the 6th i was told an e-mail is sent on my behalf-on the last call around the 10th-i was told the same thing and given a ref number,which i never got before.17/18th i got many e-mails and ref numbers asking why i would like to cancel-though i already told your agents that i am unemployed now. I was told on the recorded line that my last debit would be 1 November 2015-not to use any airtime and data that was sent in November and that i would get an e-mail confirming my cancellation + move to prepaid. 14 Oct i received airtime and data and was not told that was going to be taken if i do not use-though i paid for that on the 1 Nov debit.+- R75 was taken and i was told i can not get that back. I called 808 was told i can't call this number ,i need to call 173-meaning i was moved-though i am still waiting for that e-mail-why is it that there are agents to speak to for those on contract(808) but not those on prepaid? how is that fair? 26th Nov- i received an invoice stating that i need to pay R155 ,why? I confirmed on the call that my last debit was 1 Nov.