Vodacom aunfair upgrade!

I am so annoyed with Vodacom contracts!!! we upgraded and instead of them cancelling the old contract benefits they just added the upgrade!!! I upgraded because I wasn't using all the benefits, my needs have changed but NO vodacom just billed me for everything even after I emailed and said no upgrade wanted as the quote was almost double of the upgrade I requested... Upgrade means change the plan not add on!!!