Wrong Amount Billed

I got an alarm system installed in August 2015,I was told it's a two months free subscription that I'm getting. I was later surprised to he told that I had to pay an annual radio fee which was never mentioned in the beginning, I was left with no choice but pay it. Now beginning of December I'm being billed a ridiculous amount and I'm told it includes the annual radio fee,for starters I don't what fee that is but I paid initially but being charged again within just 2 months! Maybe I don't understand the English word \annual"I thought it meant 12 months. Anyway I called and was transferred to the Bloemfontein branch who transferred me to their accounts department where I spoke to an arrogant man who placed me on hold and transferred back to reception without giving me answers. Called the Bloem branch asked for the manager and I was told he was busy"