NO REFUND ON CONTRACT THAT WAS CANCELLED 14 MONTHS AGO

I have cancelled a contract at vodacom in September 2016 already, and vodacom has still been debiting me till end of October 2017. I have only realised it now because I have numerous lines and did not check it until now. I have logged ref number 1- ********** ********** and then again ref number 1- ********** ********** and then again ref number 1- ********** ********** . First number was logged by the 24th October 2017 and still I have not been refunded by now. Every time I phone to find out when they are refunding me they cannot give me an amount and also not a date the refund will take place. I am highly frustrated. The amount is R2786.00, but they come out with different amounts every time.

PLEASE HELP ME WITH VODACOM.