My flight was delayed for one day. The given telephone number for SIXT was non responsive. Found another number on google and reported the delay. When I arrived the next day, my car was gone and the only option offered was for me to rent a larger, more expensive car at 70% extra on top of what I initially was going to pay. On my previous two trips to Holland I had similar delays with cars rented through different companies, and they set me up with other (upgraded) cars at no extra expense..