Bridging of cellphone excess terms & conditions

I made a cellphone insurance claim with vodacom and they charging more than the 15% excess and also including a 9% markup for betterment though the gadget I choose is within my price bracket of my insurance cover. Please advise how this markup price is being charged, because as per contract term and conditions it says I'll pay 15% of replacement value but now the replacement value is more than the advertised price of the cellphone cost. I'm not happy with this false advertising and the bridging of the contract because there's no way I read anything that has to do with adding a markup %.