Sick of Vodacom- they don’t even try to make it easy for customers

I’m so tired of vodacom. I’ve been struggling to cancel one line because I didn’t want to upgrade in February. I was billed and queried i, logged several calls during March and April. I refused to pay that one contract. I was told to pay full amount on my statement, only then will I be refunded for feb to April. I paid them. No refund. I queried this again 10 June.. of course vodacom consultant doesn’t listen... I get an sms that cancellation of my contract xxl only be done once paid.. firstly I Can’t cancel the whole contract only one line. Secondly I paid the account and vodacom just continues to Bill me. What do I do to get answers..? Do I go to the ombudsman?