How can I cancel through User Profile?

How can I add extra options (child seat, additional driver, GPS etc)?

We are a broker agency (3rd party), we only provide you a wide choice of car rentals at great prices. Additional extras are added at the pick-up and there is an additional charge for it. You can ask the agent directly at the desk but we cannot satisfy your request because we do not sell such options, extras are provided by the rental agency and are payable at the desk. To make sure the requested extra option/price will be available at the counter, please contact a car rental company directly by the phone provided in your rental voucher.

How to extend the booking if I already picked up the car?

Unfortunately it cannot be extended past pick-up time. Please inform the rental agency directly by the number provided in your rental voucher.