Pathetic, disgusting service from Telkom, how unusual!

I have been a telkom customer for many yrs for my adsl internet line. 2 months ago i received a call from a lady at Telkom asking me if I wanted to upgrade my line to a 10mbps line. I agreed, I was told my package would be uncapped internet R499 for the first 2 months going up to R699pm thereafter. Last month I got my first new bill, it was a ridiculous amount around R1700 so I called Telkom, I was told it was a billing error and given a ref number, 2 days later I got an sms to say problem resolved. This month I have just got my new invoice and yet again Telkom has charged me the incorrect amount, I called telkom today and asked to speak to a manager and I was put on hold, you then cut me off. Quite honestly I don't actually care, fibre line is almost completed here in our area and I will be moving to Vodacom fibre very soon however, I am not paying telkom another cent until you resolve this matter and send me the correct bill. Idiots!!