We often see hire cars in poor condition or worse still broken down, especially during the busy summer period. And you are right the service at the airport is sometimes poor as things just get so busy. Firms often do not have any replacement cars if you do have a problem with the car allocated.
Sometimes it's better to take a taxi from the airport and book your car at the resort though this isn't always easy in peak months.
Thanks for the review anyway which will help other visitors avoid the problems you experienced.