VODACOM NOT CANCELING CONTRACT

I took out a 5gig mobile router contract in july 2017. The router was deluvered and was faulty. I took the router to Vodacare and they agreed it was faulty. The router was returned to Vodacom (collected by Vodacom) within 7 days. I cancelled the contract immediately. REF nr 1- ********** ********** . (Spoke to Mhlanhla.) R199 is being debited from account month after month and I have made various calls to Vodacom. I again spoke to Vodacom 0n 5 Jan 2018. They promised a refund to be processed for the R199 erroneouly debited monthly. ref M2 2017/07/05. I am STILL being debited monthly, even though I have never had the router in a working condition and never utilised any data on this contract