Debited For No Reason No Service

I was debited for a contract that I cancelled and I did not use because it started 3 months later. I was telephonically contacted and offered a data contract with Vodacom in December last year. I accepted the contract and it was supposed to start in the new year on the 04th of January 2016. Vodacom only activated it last week. I didn't even use and I contacted them telling them to cancell it as it is starting 3months later than what we had agreed on. All was well and cancelled but then today I still got debited for it and I'm being told that it will not be refunded coz of what ever bs reason they gave. They basically taking my money for a service they could not give on time as agreed and do not want to give it back now.