Vodacom's brand new 27 month contract!

My contract with Vodacom started in December 2017, meaning it should've ended December 2019. In July of 2018 I migrated to a higher TopUp contract, after repeated assurance that a migration does not extend the contract period. Now my contract, for some reason, is running until end of March 2020, with both airtime and device payments going off my account every month. After repeated phonecalls they refuse to cancel my contract and have no interest in obtaining the recording of the migration call. At least in a month I will be free and switch to a different provider and actively advise people against joining Vodacom.