Over Charge then agreed

I am so irritated with cell c - the guy called me and was told that with the upgrade there wont be any charge to my shocking surprised my debit order was doubled - why? I called in spoke to a very rude guy who have no idea what is customer service, he lack listening skill he was arguing with me and did not want to listen, I asked for Team Leader she bodily told me his Team leader will tell me the same thing. I am so disappointed and I still want clarity on the double debit order and additional cost which I refuse to pay as I was told there wont be any additional cost with upgrade - I did not ask Cell C did