settlement letter /paid up letter

in 2016 i opened a contract account number I ********** -8 with vodacom which was supposed to end 2018 April with my mistake i did not call vodacom to cancel the account before April 2018 ends ,when i check my credit score in June 2018 i was in AREARS of R294.63 I try calling them for clarity yes indeed i had to cancel the contract before April 2018 end. on the 2018/07/16 i did a payment of R294.63 via EFT at checkers and i requested vodacom to close my account they said it will be closed by end of July 2018 from then they wont invoice me the line will go back to prepaid.on the 2018/08/02 i requested a settlement letter so that i can submit to credit bureaus they said i must wait for 42 hours then i will recieve my settlement letter via email until today 2018/08/08 i haven't recieve the letter i tried to call this morning(218/08/08) they said i will recieve it around 12h00 midday but nothing received ,when i call around 12h59 someone i spoke with said im still owing vodacom something like R45.00 apparently they have invoiced me .help im stuck now