No response from Vodacom

I logged my initial query with Vodacom on 19 July. To date I have received 1 call back from Vodacom on 31 July from a lady who said they would get back to me in 3 days to let me know what is going on. It is now 11 August and I am still waiting for a response. In the meantime I have been sent a bill for R6,000! They are quick to give you a bill, but not quick to sort out a query. Typical. I will not pay this bill until the query is resolved so I suggest that Vodacom get back to me as a matter of urgency because at this stage I am sick to death of the shocking service (or lack thereof) from Vodacom. I have been a customer for over 15 years but believe you me when it comes up for contract renewal, I will be cancelling both of my contracts with Vodacom. Shocking, shocking, shocking service.