Nonsense service provider. Horrible service

I took a sim card only deal with Vodacom, ran the 24 month course and started to go month to month. I pay and they load data. Decided to stop since it’s a month to month and now I owe them for the months I’m not paying but they aren’t loading the data. Why should I pay for a service that’s not delivered. Consultants are also very rude. I’m never mixing with Vodacom ever again. I got the contract on phone but can’t cancel over the phone