Incorrect billings with no valid explanations!

I am currently being placed on hold for the last 15minutes after speaking to Tevin in customer care , Felicia in upgrades and now im waiting for someone in accounts to kindly answer my call.All i want to know is why im being billed R317.00 when i agreed to a monthly charge of R179.00 for my upgrade .Tevin wasnt helpful at all lacked the patience and got irritated when i requested him to explain why i was being billed .I was then transferred to Felicia , who then put me through to accounts....and im still waiting !! full length of call and time wasted 35min