Vodacom Fibre - Bad service

Took out a Fibre contract with Vodacom last year on a promotion to get the first 3 months Fibre free. Three months was over and I wasn't billed for the Fibre in these 3 months which is correct, come the following month all of a sudden my Bill included the previous 3 months together with the new month. Contacted the accounts at Fibre and they saw on the system that I was entitled to the discount, after a week the Bill was still reflecting these 3 months and the service when phoning the Fibre team is horrible. They can't put you through to the person that you were dealing with before or to the person dealing with the account. They keep promising that the person will contact you back which also doesn't happen.