Vodacom - do humans work there??

I cannot get a response to emails sent to Vodacom to sort out a payment which they claim I haven't made. I have all sorts of proof that the payment has been paid and send emails with the proofs attached to the addresses given to me by the Vodacom Call Centre but there is no response whatsoever and no correction to my account. This has been going on for months. Instead, they harass me constantly with threatening messages. The Vodacom shops are not interested. I have been with Vodacom since cells phones came to this country. Never has there been a non-payment. How does one solve such a problem?