Oops! Kemwel is a broker so doesn't have an office. You will find the rental company on your contract will probably have an office in the airport. Ours was EuropCar. As I remember, Hertz is outside the terminal and does have a shuttle.
As mentioned look at your contract that was emailed to you for the name of the car rental company. I am always booked with Europcar. Their cars are a short walk from the terminal. Last time it was delivered right to the terminal and I only had to walk outside to the curb. There is also a shuttle. If it is Europcar ask for Ann. She is a gem.