Vodacom - useless service providers

So after my last post here, I got the usual follow up call from one of Vodacom's escalations experts. He couldn't tell me any more details regarding my problems - only recapped what had already transpired.

When I mentioned the additional amounts that need to be removed from my account, he told me that he would speak to the billings department and get back to me. Haven't heard back and tomorrow will mark another week that has gone by and nothing has been solved.

I still cannot access my statements from their app. Also, now it just states that all my balances to check my date and minutes etc, are unavailable.

When checking the balances using the USSD codes, it still states I'm on a Smart package and my data never gets renewed..

I'm at a loss about my next move with this company. Surely there is at least one person that can fix whatever the problem is? Shall I get a new sim card? Can I cancel my contract with them as they're not following through with the services that they're billing me for? Surely that's breach of contract on their part?