I was forced to purchase insurance even though i already had it doubling the cost.

I had to take a shuttle to pick up the car. When i showed up they forced me to purchase their insurance even though i already did with my own insurance company at a fraction of the cost. This almost doubled my cost and was told they won't shuttle me back to the airport to go with another company. They also wouldn't allow me to rent for 1 day so i could find a better price elsewhere. I have rented with other companies and used my insurance many times. Other companies may cost more at booking but do not have these extra fees. I will never use this scam company again.