Online insurance ***** or ****

After numerous phone calls to Sicily by Car trying to sort out my refund it emerges that the staff at the counters don't advise or guarantee the online insurance that airportrentals dot com is selling and that is why they are selling extra cover when picking up the vehicles on arrival. I was informed by Sicily by car that if I don't take the top up insurance with them the excess would be deducted from my credit card in the event of theft or accident damage. It is unacceptable and airportrentals dot com needs to sort out their agreements with their rental suppliers or stop selling additional insurance online. Please refund the 264 euro that was deducted on my credit card. I have also lodged a complaint with Sicily by car to investigate this.