Sales and Billing don't speak to each other

I was a moderately satisfied ADSL customer. Then a salesman phoned to say that they can switch me to Fibre on a like-for-like basis - no extra cost for me. So I gave the go-ahead and the technical job was completed without issues. Then my first bill arrived - R200 above what I normally pay. So I phone the billing department. They confirmed that the Fibre costs are correct on my bill, if I have an issue with it I must take it up with Sales. Phoned Sales (who have no access to billing information) who confirmed that my total bill should have been unchanged and they will make a note for the billing department. A month later and the problem hasn't been rectified. Another +-R200 extra on my bill. Billing department can't help. Sales department are offline and can't even arrange for someone to call me when they are back online. I must just try again later, be on hold for another 15 minutes, and be told that they are offline. I didn't want to move from Telkom because it's convenient having landline and data all though one provider, but they are making it very difficult to do business with them.